In my webshop I have Ideal. When I put the code of the idealform from the bank in the extrapayment info then the for appears in the confirmationmail because I have arranged that extra paymentinfo will appear also in this mail. Therefor I have put the code of the Idealform in the checkoutthankyou directory. The only thing is that the form appears on the page at all paying methods. I am looking for a php code to arrange this. I have something like this but it doesn't work. My php-know how is bad.
<?php if(PAYMENT_METHOD_ID == 'ID') {?><form>
Are you using VM2.0?
Anyway, adding iDEAL like that is hard, because the PHP code needs to be adjusted. You can't just copy paste it. That is why we created a component for iDEAL in Virtuemart 2.0:
http://www.joomlavirtuemartideal.nl/easy-ideal-joomla-virtuemart-component-module.html
You can try, but you need more PHP knowledge if you do it yourself.