diff -ru roundcubemail.old/plugins/new_user_identity/new_user_identity.php roundcubemail/plugins/new_user_identity/new_user_identity.php
--- roundcubemail.old/plugins/new_user_identity/new_user_identity.php	2011-02-03 01:55:05.000000000 -0800
+++ roundcubemail/plugins/new_user_identity/new_user_identity.php	2011-02-03 02:14:57.000000000 -0800
@@ -35,7 +35,7 @@
         if ($addressbook = $rcmail->config->get('new_user_identity_addressbook')) {
             $match = $rcmail->config->get('new_user_identity_match');
             $ldap = $rcmail->get_address_book($addressbook);
-            $ldap->prop['search_fields'] = array($match);
+            $ldap->set_search_fields($match);
             $results = $ldap->search($match, $args['user'], TRUE);
             if (count($results->records) == 1) {
                 $args['user_name'] = $results->records[0]['name'];
diff -ru roundcubemail.old/program/include/rcube_ldap.php roundcubemail/program/include/rcube_ldap.php
--- roundcubemail.old/program/include/rcube_ldap.php	2011-02-03 01:55:05.000000000 -0800
+++ roundcubemail/program/include/rcube_ldap.php	2011-02-03 02:14:20.000000000 -0800
@@ -307,6 +307,15 @@
     return $this->filter;
   }
 
+ /**
+  * Override the search fields
+  * 
+  * @param array Search fields used by this class
+  */
+  function set_search_fields($fields)
+  {
+    $this->prop['search_fields'] = (array)$fields;
+  }
 
   /**
    * Reset all saved results and search parameters