/**
  * Check partial refund availability for invoice
  *
  * @return bool
  */
 public function canRefundPartialPerInvoice()
 {
     $enable_refund = Mage::getStoreConfig('pay_payment/general/enable_refund');
     if (!$enable_refund) {
         return false;
     } else {
         return parent::canRefundPartialPerInvoice();
     }
 }