diff --git a/plugins/kolab_core/config.inc.php.dist b/plugins/kolab_core/config.inc.php.dist
index b6ac25a4..c107a2f7 100644
--- a/plugins/kolab_core/config.inc.php.dist
+++ b/plugins/kolab_core/config.inc.php.dist
@@ -1,6 +1,8 @@
 <?php
 
 // Sample configuration for Kolab LDAP binding used by Kolab_Storage
+
+//$rcmail_config['kolab']['ldap']['server'] = '<defaults to imap_host>';
 $rcmail_config['kolab']['ldap']['basedn'] = 'dc=kolabserver,dc=local';
 $rcmail_config['kolab']['ldap']['phpdn'] = 'cn=nobody,cn=internal,dc=kolabserver,dc=local';
 $rcmail_config['kolab']['ldap']['phppw'] = '<ldap-pwd-goes-here>';
diff --git a/plugins/kolab_core/rcube_kolab.php b/plugins/kolab_core/rcube_kolab.php
index a69a9036..fb9c975e 100644
--- a/plugins/kolab_core/rcube_kolab.php
+++ b/plugins/kolab_core/rcube_kolab.php
@@ -34,9 +34,8 @@ class rcube_kolab
         // load ldap credentials from local config
         $conf['kolab'] = $rcmail->config->get('kolab');
         
-        $conf['kolab']['ldap']['server'] = 'ldap://' . $_SESSION['imap_host'] . ':389';
-        $conf['kolab']['imap']['server'] = $_SESSION['imap_host'];
-        $conf['kolab']['imap']['port'] = $_SESSION['imap_port'];
+        $conf['kolab']['ldap'] += array('server' => 'ldap://' . $_SESSION['imap_host'] . ':389');
+        $conf['kolab']['imap'] = array('server' => $_SESSION['imap_host'], 'port' => $_SESSION['imap_port']);
         
         // pass the current IMAP authentication credentials to the Horde auth system
         self::$horde_auth = Auth::singleton('kolab');