protected function createAlias($transaction, $parameters)
 {
     $url = $this->getFormActionUrl($transaction);
     $response = Customweb_Saferpay_Util::sendFormData($url, $parameters);
     if (isset($response['location'])) {
         $transaction->setTransactionState(Customweb_Saferpay_Authorization_Transaction::STATE_ALIAS_EXISTS);
         $transaction->setNextRedirectUrl($response['location']);
     } else {
         $reason = Customweb_I18n_Translation::__("Server responded with unexpected headers '!response'", array('!response' => print_r($response, true)));
         $transaction->setAuthorizationFailed($reason);
         $this->redirect(null, $transaction, $this->getFailedUrl($transaction));
     }
 }