You should be well acquainted with Joomla and Virtuemart since I need this solution fast.
I anticipate that you already know that Virtuemart sends an order confirmation email to the buyer already before the payment procedure is initiated. I want to
1) stop this order confirmation email from being sent (minor hack)
2) make Virtuemart send the order confirmation email when the payment processor changes the order status to “Confirmed”.
I use a certain payment module for Virtuemart that is written according to Virtuemart developer guidelines and code is commented in English.
In order to make this function insensible to future Virtuemart upgrades, this function should if possible be added to the payment module, rather than hacking the Virtuemart code.
I will provide a functioning test-environment where you have full admin and FTP-access. Even the payment processor is functioning in test-mode so you can make test-payments.
Payment module is attached.