1. ps_checkout.php: Create a function like the "email_receipt"-function starting on line 1761.
2. ps_main.php: Create a function like the "vmMail"-function starting on line 548.
1. copy the confirmation_email.tpl.php and name the new file something like confirmation_email_2.tpl.php
2. Change the content of this mail, this is your second mail sendt to the costumer
Go back to administrator/components/com_virtuemart/classes and change the line "$shopper_html = $template->fetch('order_emails/confirmation_email.tpl.php');" of your new "email_receipt"-function to ""$shopper_html = $template->fetch('order_emails/confirmation_email_2.tpl.php');".