protected function callbackExceptionHandler(Exception $ex)
 {
     switch ($case = $this->callback_protocol) {
         case self::SOAP:
             $result = parent::callbackExceptionHandler($ex);
             break;
         case self::REST:
             $result = array('template' => $this->path . '/templates/resultRest.html', 'result_code' => $ex->getCode(), 'header' => array('Content-type' => 'text/xml; charset=utf-8;'));
             break;
         default:
             $result = array('error' => 'unknown protocol');
     }
     return $result;
 }