403014 Virtuemart - Send serialnumber

I would like to be able to send serial numbers when a downloadble product is purchased. The serial numbers Would ask Stored in a table, Together with the product ID and I Would populator this data manually through the admin area. If customer has payed, and his order's state will be "confirmed" (from "pending"), then an email is sent to him with the product serial. Note: We just want to sell just 1 product/license per order! Customer can see his serials also visiting his orders (depends on state), and vendor is always able to see them. System: Joomla 1.5.15 (new installation) & Virtuemart 1.1.4 stable