#20 add transaction id to invoice so that online refund is possible

Model/Method/Cc.php

@@ -339,6 +339,11 @@ class Cc extends \Magento\Payment\Model\Method\Cc
     public function capture(\Magento\Payment\Model\InfoInterface $payment, $amount)
     {
         parent::capture($payment, $amount);
+
+        // set TransactionId so you can do an online refund
+        $payment->setTransactionId(1)
+                ->setIsTransactionClosed(false);
+
         $this->_paymentRequest->capture($payment, $amount);
         return $this;
     }

Model/Method/Hpp.php

@@ -380,6 +380,11 @@ class Hpp extends \Magento\Payment\Model\Method\AbstractMethod implements Gatewa
     public function capture(\Magento\Payment\Model\InfoInterface $payment, $amount)
     {
         parent::capture($payment, $amount);
+
+        // set TransactionId so you can do an online refund
+        $payment->setTransactionId(1)
+            ->setIsTransactionClosed(false);
+
         $this->_paymentRequest->capture($payment, $amount);
         return $this;
     }

Model/Method/Pos.php

@@ -380,6 +380,11 @@ class Pos extends \Magento\Payment\Model\Method\AbstractMethod implements Gatewa
     public function capture(\Magento\Payment\Model\InfoInterface $payment, $amount)
     {
         parent::capture($payment, $amount);
+
+        // set TransactionId so you can do an online refund
+        $payment->setTransactionId(1)
+            ->setIsTransactionClosed(false);
+
         $this->_paymentRequest->capture($payment, $amount);
         return $this;
     }