diff --git a/plugins/libkolab/lib/kolab_storage_folder.php b/plugins/libkolab/lib/kolab_storage_folder.php
index 461125b3..7c28eff5 100644
--- a/plugins/libkolab/lib/kolab_storage_folder.php
+++ b/plugins/libkolab/lib/kolab_storage_folder.php
@@ -1,849 +1,861 @@
 <?php
 
 /**
  * The kolab_storage_folder class represents an IMAP folder on the Kolab server.
  *
  * @version @package_version@
  * @author Thomas Bruederli <bruederli@kolabsys.com>
  *
  * Copyright (C) 2012, Kolab Systems AG <contact@kolabsys.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as
  * published by the Free Software Foundation, either version 3 of the
  * License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU Affero General Public License for more details.
  *
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 class kolab_storage_folder
 {
     /**
      * The folder name.
      * @var string
      */
     public $name;
 
     /**
      * The type of this folder.
      * @var string
      */
     public $type;
 
     /**
      * Is this folder set to be the default for its type
      * @var boolean
      */
     public $default = false;
 
     /**
      * Is this folder set to be default
      * @var boolean
      */
     public $cache;
 
     private $type_annotation;
     private $imap;
     private $info;
     private $owner;
     private $resource_uri;
     private $uid2msg = array();
 
 
     /**
      * Default constructor
      */
     function __construct($name, $type = null)
     {
         $this->imap = rcube::get_instance()->get_storage();
         $this->imap->set_options(array('skip_deleted' => true));
         $this->cache = new kolab_storage_cache($this);
         $this->set_folder($name, $type);
     }
 
 
     /**
      * Set the IMAP folder this instance connects to
      *
      * @param string The folder name/path
      * @param string Optional folder type if known
      */
     public function set_folder($name, $ftype = null)
     {
         $this->type_annotation = $ftype ? $ftype : kolab_storage::folder_type($name);
 
         list($this->type, $suffix) = explode('.', $this->type_annotation);
         $this->default      = $suffix == 'default';
         $this->name         = $name;
         $this->resource_uri = null;
 
         $this->imap->set_folder($this->name);
         $this->cache->set_folder($this);
     }
 
 
     /**
      *
      */
     private function get_folder_info()
     {
         if (!isset($this->info))
             $this->info = $this->imap->folder_info($this->name);
 
         return $this->info;
     }
 
 
     /**
      * Returns IMAP metadata/annotations (GETMETADATA/GETANNOTATION)
      *
      * @param array List of metadata keys to read
      * @return array Metadata entry-value hash array on success, NULL on error
      */
     public function get_metadata($keys)
     {
         $metadata = $this->imap->get_metadata($this->name, (array)$keys);
         return $metadata[$this->name];
     }
 
 
     /**
      * Sets IMAP metadata/annotations (SETMETADATA/SETANNOTATION)
      *
      * @param array  $entries Entry-value array (use NULL value as NIL)
      * @return boolean True on success, False on failure
      */
     public function set_metadata($entries)
     {
         return $this->imap->set_metadata($this->name, $entries);
     }
 
 
     /**
      * Returns the owner of the folder.
      *
      * @return string  The owner of this folder.
      */
     public function get_owner()
     {
         // return cached value
         if (isset($this->owner))
             return $this->owner;
 
         $info = $this->get_folder_info();
         $rcmail = rcube::get_instance();
 
         switch ($info['namespace']) {
         case 'personal':
             $this->owner = $rcmail->get_user_name();
             break;
 
         case 'shared':
             $this->owner = 'anonymous';
             break;
 
         default:
             $owner = '';
             list($prefix, $user) = explode($this->imap->get_hierarchy_delimiter(), $info['name']);
             if (strpos($user, '@') === false) {
                 $domain = strstr($rcmail->get_user_name(), '@');
                 if (!empty($domain))
                     $user .= $domain;
             }
             $this->owner = $user;
             break;
         }
 
         return $this->owner;
     }
 
 
     /**
      * Getter for the name of the namespace to which the IMAP folder belongs
      *
      * @return string Name of the namespace (personal, other, shared)
      */
     public function get_namespace()
     {
         return $this->imap->folder_namespace($this->name);
     }
 
 
     /**
      * Get IMAP ACL information for this folder
      *
      * @return string  Permissions as string
      */
     public function get_myrights()
     {
         $rights = $this->info['rights'];
 
         if (!is_array($rights))
             $rights = $this->imap->my_rights($this->name);
 
         return join('', (array)$rights);
     }
 
 
     /**
      * Compose a unique resource URI for this IMAP folder
      */
     public function get_resource_uri()
     {
         if (!empty($this->resource_uri))
             return $this->resource_uri;
 
         // strip namespace prefix from folder name
         $ns = $this->get_namespace();
         $nsdata = $this->imap->get_namespace($ns);
         if (is_array($nsdata[0]) && strlen($nsdata[0][0]) && strpos($this->name, $nsdata[0][0]) === 0) {
             $subpath = substr($this->name, strlen($nsdata[0][0]));
             if ($ns == 'other') {
                 list($user, $suffix) = explode($nsdata[0][1], $subpath);
                 $subpath = $suffix;
             }
         }
         else {
             $subpath = $this->name;
         }
 
         // compose fully qualified ressource uri for this instance
         $this->resource_uri = 'imap://' . urlencode($this->get_owner()) . '@' . $this->imap->options['host'] . '/' . $subpath;
         return $this->resource_uri;
     }
 
     /**
      * Check subscription status of this folder
      *
      * @param string Subscription type (kolab_storage::SERVERSIDE_SUBSCRIPTION or kolab_storage::CLIENTSIDE_SUBSCRIPTION)
      * @return boolean True if subscribed, false if not
      */
     public function is_subscribed($type = 0)
     {
         static $subscribed;  // local cache
 
         if ($type == kolab_storage::SERVERSIDE_SUBSCRIPTION) {
             if (!$subscribed)
                 $subscribed = $this->imap->list_folders_subscribed();
 
             return in_array($this->name, $subscribed);
         }
         else if (kolab_storage::CLIENTSIDE_SUBSCRIPTION) {
             // TODO: implement this
             return true;
         }
 
         return false;
     }
 
     /**
      * Change subscription status of this folder
      *
      * @param boolean The desired subscription status: true = subscribed, false = not subscribed
      * @param string  Subscription type (kolab_storage::SERVERSIDE_SUBSCRIPTION or kolab_storage::CLIENTSIDE_SUBSCRIPTION)
      * @return True on success, false on error
      */
     public function subscribe($subscribed, $type = 0)
     {
         if ($type == kolab_storage::SERVERSIDE_SUBSCRIPTION) {
             return $subscribed ? $this->imap->subscribe($this->name) : $this->imap->unsubscribe($this->name);
         }
         else {
           // TODO: implement this
         }
 
         return false;
     }
 
 
     /**
      * Get number of objects stored in this folder
      *
      * @param mixed  Pseudo-SQL query as list of filter parameter triplets
      *    or string with object type (e.g. contact, event, todo, journal, note, configuration)
      * @return integer The number of objects of the given type
      * @see self::select()
      */
     public function count($type_or_query = null)
     {
         if (!$type_or_query)
             $query = array(array('type','=',$this->type));
         else if (is_string($type_or_query))
             $query = array(array('type','=',$type_or_query));
         else
             $query = $this->_prepare_query((array)$type_or_query);
 
         // synchronize cache first
         $this->cache->synchronize();
 
         return $this->cache->count($query);
     }
 
 
     /**
      * List all Kolab objects of the given type
      *
      * @param string  $type Object type (e.g. contact, event, todo, journal, note, configuration)
      * @return array  List of Kolab data objects (each represented as hash array)
      */
     public function get_objects($type = null)
     {
         if (!$type) $type = $this->type;
 
         // synchronize caches
         $this->cache->synchronize();
 
         // fetch objects from cache
         return $this->cache->select(array(array('type','=',$type)));
     }
 
 
     /**
      * Select *some* Kolab objects matching the given query
      *
      * @param array Pseudo-SQL query as list of filter parameter triplets
      *   triplet: array('<colname>', '<comparator>', '<value>')
      * @return array List of Kolab data objects (each represented as hash array)
      */
     public function select($query = array())
     {
         // check query argument
         if (empty($query))
             return $this->get_objects();
 
         // synchronize caches
         $this->cache->synchronize();
 
         // fetch objects from cache
         return $this->cache->select($this->_prepare_query($query));
     }
 
 
     /**
      * Getter for object UIDs only
      *
      * @param array Pseudo-SQL query as list of filter parameter triplets
      * @return array List of Kolab object UIDs
      */
     public function get_uids($query = array())
     {
         // synchronize caches
         $this->cache->synchronize();
 
         // fetch UIDs from cache
         return $this->cache->select($this->_prepare_query($query), true);
     }
 
 
     /**
      * Helper method to sanitize query arguments
      */
     private function _prepare_query($query)
     {
         $type = null;
         foreach ($query as $i => $param) {
             if ($param[0] == 'type') {
                 $type = $param[2];
             }
             else if (($param[0] == 'dtstart' || $param[0] == 'dtend' || $param[0] == 'changed')) {
                 if (is_object($param[2]) && is_a($param[2], 'DateTime'))
                     $param[2] = $param[2]->format('U');
                 if (is_numeric($param[2]))
                     $query[$i][2] = date('Y-m-d H:i:s', $param[2]);
             }
         }
 
         // add type selector if not in $query
         if (!$type)
             $query[] = array('type','=',$this->type);
 
         return $query;
     }
 
 
     /**
      * Getter for a single Kolab object, identified by its UID
      *
      * @param string Object UID
      * @return array The Kolab object represented as hash array
      */
     public function get_object($uid)
     {
         // synchronize caches
         $this->cache->synchronize();
 
         $msguid = $this->cache->uid2msguid($uid);
         if ($msguid && ($object = $this->cache->get($msguid)))
             return $object;
 
         return false;
     }
 
 
     /**
      * Fetch a Kolab object attachment which is stored in a separate part
      * of the mail MIME message that represents the Kolab record.
      *
      * @param string  Object's UID
      * @param string  The attachment's mime number
      * @param string  IMAP folder where message is stored;
      *                If set, that also implies that the given UID is an IMAP UID
      * @return mixed  The attachment content as binary string
      */
     public function get_attachment($uid, $part, $mailbox = null)
     {
         if ($msguid = ($mailbox ? $uid : $this->cache->uid2msguid($uid))) {
             $this->imap->set_folder($mailbox ? $mailbox : $this->name);
             return $this->imap->get_message_part($msguid, $part);
         }
 
         return null;
     }
 
 
     /**
      * Fetch the mime message from the storage server and extract
      * the Kolab groupware object from it
      *
      * @param string The IMAP message UID to fetch
      * @param string The object type expected (use wildcard '*' to accept all types)
      * @param string The folder name where the message is stored
      * @return mixed Hash array representing the Kolab object, a kolab_format instance or false if not found
      */
     public function read_object($msguid, $type = null, $folder = null)
     {
         if (!$type) $type = $this->type;
         if (!$folder) $folder = $this->name;
 
         $this->imap->set_folder($folder);
 
         $headers = $this->imap->get_message_headers($msguid);
 
         // Message doesn't exist?
         if (empty($headers)) {
             return false;
         }
 
         $object_type = kolab_format::mime2object_type($headers->others['x-kolab-type']);
         $content_type  = kolab_format::KTYPE_PREFIX . $object_type;
 
         // check object type header and abort on mismatch
         if ($type != '*' && $object_type != $type)
             return false;
 
         $message = new rcube_message($msguid);
         $attachments = array();
 
         // get XML part
         foreach ((array)$message->attachments as $part) {
             if (!$xml && ($part->mimetype == $content_type || preg_match('!application/([a-z]+\+)?xml!', $part->mimetype))) {
                 $xml = $part->body ? $part->body : $message->get_part_content($part->mime_id);
             }
             else if ($part->filename || $part->content_id) {
                 $key  = $part->content_id ? trim($part->content_id, '<>') : $part->filename;
                 $size = null;
 
                 // Use Content-Disposition 'size' as for the Kolab Format spec.
                 if (isset($part->d_parameters['size'])) {
                     $size = $part->d_parameters['size'];
                 }
                 // we can trust part size only if it's not encoded
                 else if ($part->encoding == 'binary' || $part->encoding == '7bit' || $part->encoding == '8bit') {
                     $size = $part->size;
                 }
 
                 $attachments[$key] = array(
                     'id'       => $part->mime_id,
                     'name'     => $part->filename,
                     'mimetype' => $part->mimetype,
                     'size'     => $size,
                 );
             }
         }
 
         if (!$xml) {
             rcube::raise_error(array(
                 'code' => 600,
                 'type' => 'php',
                 'file' => __FILE__,
                 'line' => __LINE__,
                 'message' => "Could not find Kolab data part in message $msguid ($this->name).",
             ), true);
             return false;
         }
 
         $format = kolab_format::factory($object_type);
 
         if (is_a($format, 'PEAR_Error'))
             return false;
 
         // check kolab format version
         $mime_version = $headers->others['x-kolab-mime-version'];
         if (empty($mime_version)) {
             list($xmltype, $subtype) = explode('.', $object_type);
             $xmlhead = substr($xml, 0, 512);
 
             // detect old Kolab 2.0 format
             if (strpos($xmlhead, '<' . $xmltype) !== false && strpos($xmlhead, 'xmlns=') === false)
                 $mime_version = 2.0;
             else
                 $mime_version = 3.0; // assume 3.0
         }
 
         if ($mime_version <= 2.0) {
             // read Kolab 2.0 format
             $handler = class_exists('Horde_Kolab_Format') ? Horde_Kolab_Format::factory('XML', $xmltype, array('subtype' => $subtype)) : null;
             if (!is_object($handler) || is_a($handler, 'PEAR_Error')) {
                 return false;
             }
 
             // XML-to-array
             $object = $handler->load($xml);
             $format->fromkolab2($object);
         }
         else {
             // load Kolab 3 format using libkolabxml
             $format->load($xml);
         }
 
         if ($format->is_valid()) {
             $object = $format->to_array();
             $object['_type'] = $object_type;
             $object['_msguid'] = $msguid;
             $object['_mailbox'] = $this->name;
             $object['_attachments'] = array_merge((array)$object['_attachments'], $attachments);
             $object['_formatobj'] = $format;
 
             return $object;
         }
         else {
             // try to extract object UID from XML block
             if (preg_match('!<uid>(.+)</uid>!Uims', $xml, $m))
                 $msgadd = " UID = " . trim(strip_tags($m[1]));
 
             rcube::raise_error(array(
                 'code' => 600,
                 'type' => 'php',
                 'file' => __FILE__,
                 'line' => __LINE__,
                 'message' => "Could not parse Kolab object data in message $msguid ($this->name)." . $msgadd,
             ), true);
         }
 
         return false;
     }
 
 
     /**
      * Save an object in this folder.
      *
      * @param array  $object    The array that holds the data of the object.
      * @param string $type      The type of the kolab object.
      * @param string $uid       The UID of the old object if it existed before
      * @return boolean          True on success, false on error
      */
     public function save(&$object, $type = null, $uid = null)
     {
         if (!$type)
             $type = $this->type;
 
         // copy attachments from old message
         if (!empty($object['_msguid']) && ($old = $this->cache->get($object['_msguid'], $type, $object['_mailbox']))) {
             foreach ((array)$old['_attachments'] as $key => $att) {
                 if (!isset($object['_attachments'][$key])) {
                     $object['_attachments'][$key] = $old['_attachments'][$key];
                 }
                 // unset deleted attachment entries
                 if ($object['_attachments'][$key] == false) {
                     unset($object['_attachments'][$key]);
                 }
                 // load photo.attachment from old Kolab2 format to be directly embedded in xcard block
                 else if ($key == 'photo.attachment' && !isset($object['photo']) && !$object['_attachments'][$key]['content'] && $att['id']) {
                     $object['photo'] = $this->get_attachment($object['_msguid'], $att['id'], $object['_mailbox']);
                     unset($object['_attachments'][$key]);
                 }
             }
         }
 
-        // generate unique keys (used as content-id) for attachments
+        // Parse attachments
         if (is_array($object['_attachments'])) {
             $numatt = count($object['_attachments']);
             foreach ($object['_attachments'] as $key => $attachment) {
+                // make sure size is set, so object saved in cache contains this info
+                if (!isset($attachment['size'])) {
+                    if (!empty($attachment['content'])) {
+                        $attachment['size'] = strlen($attachment['content']);
+                    }
+                    else if (!empty($attachment['path'])) {
+                        $attachment['size'] = filesize($attachment['path']);
+                    }
+                    $object['_attachments'][$key] = $attachment;
+                }
+
+                // generate unique keys (used as content-id) for attachments
                 if (is_numeric($key) && $key < $numatt) {
                     // derrive content-id from attachment file name
                     $ext = preg_match('/(\.[a-z0-9]{1,6})$/i', $attachment['name'], $m) ? $m[1] : null;
                     $basename = preg_replace('/[^a-z0-9_.-]/i', '', basename($attachment['name'], $ext));  // to 7bit ascii
                     if (!$basename) $basename = 'noname';
                     $cid = $basename . '.' . microtime(true) . $ext;
 
                     $object['_attachments'][$cid] = $attachment;
                     unset($object['_attachments'][$key]);
                 }
             }
         }
 
         if ($raw_msg = $this->build_message($object, $type)) {
             $result = $this->imap->save_message($this->name, $raw_msg, '', false);
 
             // delete old message
             if ($result && !empty($object['_msguid']) && !empty($object['_mailbox'])) {
                 $this->imap->delete_message($object['_msguid'], $object['_mailbox']);
                 $this->cache->set($object['_msguid'], false, $object['_mailbox']);
             }
             else if ($result && $uid && ($msguid = $this->cache->uid2msguid($uid))) {
                 $this->imap->delete_message($msguid, $this->name);
                 $this->cache->set($object['_msguid'], false);
             }
 
             // update cache with new UID
             if ($result) {
                 $object['_msguid'] = $result;
                 $this->cache->insert($result, $object);
             }
         }
         
         return $result;
     }
 
 
     /**
      * Delete the specified object from this folder.
      *
      * @param  mixed   $object  The Kolab object to delete or object UID
      * @param  boolean $expunge Should the folder be expunged?
      *
      * @return boolean True if successful, false on error
      */
     public function delete($object, $expunge = true)
     {
         $msguid = is_array($object) ? $object['_msguid'] : $this->cache->uid2msguid($object);
         $success = false;
 
         if ($msguid && $expunge) {
             $success = $this->imap->delete_message($msguid, $this->name);
         }
         else if ($msguid) {
             $success = $this->imap->set_flag($msguid, 'DELETED', $this->name);
         }
 
         if ($success) {
             $this->cache->set($msguid, false);
         }
 
         return $success;
     }
 
 
     /**
      *
      */
     public function delete_all()
     {
         $this->cache->purge();
         return $this->imap->clear_folder($this->name);
     }
 
 
     /**
      * Restore a previously deleted object
      *
      * @param string Object UID
      * @return mixed Message UID on success, false on error
      */
     public function undelete($uid)
     {
         if ($msguid = $this->cache->uid2msguid($uid, true)) {
             if ($this->imap->set_flag($msguid, 'UNDELETED', $this->name)) {
                 return $msguid;
             }
         }
 
         return false;
     }
 
 
     /**
      * Move a Kolab object message to another IMAP folder
      *
      * @param string Object UID
      * @param string IMAP folder to move object to
      * @return boolean True on success, false on failure
      */
     public function move($uid, $target_folder)
     {
         if ($msguid = $this->cache->uid2msguid($uid)) {
             if ($success = $this->imap->move_message($msguid, $target_folder, $this->name)) {
                 $this->cache->move($msguid, $uid, $target_folder);
                 return true;
             }
             else {
                 rcube::raise_error(array(
                     'code' => 600, 'type' => 'php',
                     'file' => __FILE__, 'line' => __LINE__,
                     'message' => "Failed to move message $msguid to $target_folder: " . $this->imap->get_error_str(),
                 ), true);
             }
         }
 
         return false;
     }
 
 
     /**
      * Creates source of the configuration object message
      */
     private function build_message(&$object, $type)
     {
         // load old object to preserve data we don't understand/process
         if (is_object($object['_formatobj']))
             $format = $object['_formatobj'];
         else if ($object['_msguid'] && ($old = $this->cache->get($object['_msguid'], $type, $object['_mailbox'])))
             $format = $old['_formatobj'];
 
         // create new kolab_format instance
         if (!$format)
             $format = kolab_format::factory($type);
 
         if (PEAR::isError($format))
             return false;
 
         $format->set($object);
         $xml = $format->write();
         $object['uid'] = $format->uid;  // read UID from format
         $object['_formatobj'] = $format;
 
         if (!$format->is_valid() || empty($object['uid'])) {
             return false;
         }
 
         $mime = new Mail_mime("\r\n");
         $rcmail = rcube::get_instance();
         $headers = array();
         $part_id = 1;
 
         if ($ident = $rcmail->user->get_identity()) {
             $headers['From'] = $ident['email'];
             $headers['To'] = $ident['email'];
         }
         $headers['Date'] = date('r');
         $headers['X-Kolab-Type'] = kolab_format::KTYPE_PREFIX . $type;
         $headers['X-Kolab-Mime-Version'] = kolab_format::VERSION;
         $headers['Subject'] = $object['uid'];
 //        $headers['Message-ID'] = $rcmail->gen_message_id();
         $headers['User-Agent'] = $rcmail->config->get('useragent');
 
         $mime->headers($headers);
         $mime->setTXTBody('This is a Kolab Groupware object. '
             . 'To view this object you will need an email client that understands the Kolab Groupware format. '
             . "For a list of such email clients please visit http://www.kolab.org/\n\n");
 
         $mime->addAttachment($xml,  // file
             $format->CTYPE,         // content-type
             'kolab.xml',            // filename
             false,                  // is_file
             '8bit',                 // encoding
             'attachment',           // disposition
             RCMAIL_CHARSET          // charset
         );
         $part_id++;
 
         // save object attachments as separate parts
         // TODO: optimize memory consumption by using tempfiles for transfer
         foreach ((array)$object['_attachments'] as $key => $att) {
             if (empty($att['content']) && !empty($att['id'])) {
                 $msguid = !empty($object['_msguid']) ? $object['_msguid'] : $object['uid'];
                 $att['content'] = $this->get_attachment($msguid, $att['id'], $object['_mailbox']);
             }
 
             $headers = array('Content-ID' => Mail_mimePart::encodeHeader('Content-ID', '<' . $key . '>', RCMAIL_CHARSET, 'quoted-printable'));
             $name = !empty($att['name']) ? $att['name'] : $key;
 
             if (!empty($att['content'])) {
                 $mime->addAttachment($att['content'], $att['mimetype'], $name, false, 'base64', 'attachment', '', '', '', null, null, '', RCMAIL_CHARSET, $headers);
                 $part_id++;
             }
             else if (!empty($att['path'])) {
                 $mime->addAttachment($att['path'], $att['mimetype'], $name, true, 'base64', 'attachment', '', '', '', null, null, '', RCMAIL_CHARSET, $headers);
                 $part_id++;
             }
 
             $object['_attachments'][$key]['id'] = $part_id;
         }
 
         return $mime->getMessage();
     }
 
 
     /**
      * Triggers any required updates after changes within the
      * folder. This is currently only required for handling free/busy
      * information with Kolab.
      *
      * @return boolean|PEAR_Error True if successfull.
      */
     public function trigger()
     {
         $owner = $this->get_owner();
         $result = false;
 
         switch($this->type) {
         case 'event':
             if ($this->get_namespace() == 'personal') {
                 $result = $this->trigger_url(
                     sprintf('%s/trigger/%s/%s.pfb', kolab_storage::get_freebusy_server(), $owner, $this->imap->mod_folder($this->name)),
                     $this->imap->options['user'],
                     $this->imap->options['password']
                 );
             }
             break;
 
         default:
             return true;
         }
 
         if ($result && is_object($result) && is_a($result, 'PEAR_Error')) {
             return PEAR::raiseError(sprintf("Failed triggering folder %s. Error was: %s",
                                             $this->name, $result->getMessage()));
         }
 
         return $result;
     }
 
     /**
      * Triggers a URL.
      *
      * @param string $url          The URL to be triggered.
      * @param string $auth_user    Username to authenticate with
      * @param string $auth_passwd  Password for basic auth
      * @return boolean|PEAR_Error  True if successfull.
      */
     private function trigger_url($url, $auth_user = null, $auth_passwd = null)
     {
         require_once('HTTP/Request2.php');
 
         try {
             $rcmail = rcube::get_instance();
             $request = new HTTP_Request2($url);
             $request->setConfig(array('ssl_verify_peer' => $rcmail->config->get('kolab_ssl_verify_peer', true)));
 
             // set authentication credentials
             if ($auth_user && $auth_passwd)
                 $request->setAuth($auth_user, $auth_passwd);
 
             $result = $request->send();
             // rcube::write_log('trigger', $result->getBody());
         }
         catch (Exception $e) {
             return PEAR::raiseError($e->getMessage());
         }
 
         return true;
     }
 
 }