/**
  * Set reference transaction data into request
  *
  * @param Varien_Object $payment
  * @param Varien_Object $request
  * @return Mage_Paypal_Model_Payflowlink
  */
 protected function _setReferenceTransaction(Varien_Object $payment, $request)
 {
     if ($payment->getParentTransactionId()) {
         $request->setOrigid($payment->getParentTransactionId());
         $request->unsAcct();
         $request->unsExpdate();
         $request->unsCvv2();
     }
     return $this;
 }