public static function registerZend()
 {
     if (!self::$zendAutoLoader) {
         set_include_path(implode(PATH_SEPARATOR, array(sfConfig::get('sf_lib_dir') . '/vendor/', get_include_path())));
         require_once 'Zend/Loader/Autoloader.php';
         self::$zendAutoLoader = Zend_Loader_Autoloader::getInstance();
     }
     return self::$zendAutoLoader;
 }