VirtueMart Joomla custom item

We need custom module/hack for Virtuemart. We have to sale unique PIN numbers for activating our service. For example: Item: "PIN number for service xy1" We have for example PIN numbers for sale: 1215643xy 2435554sd 2343559ds etc... When customer purchase "PIN number for service xy1"; VM must after payment is made, send mail to customer with first available PIN number "1215643xy". That PIN number must be after is sold "taged as sold". In admin console must be visible but taged as sold. Customers doesn't see PIN number in VM in purchasing process, they get it on mail. Mail to customer must have option to customize it. Every item like "PIN number for service xy1" must have option to add unique PIN numbers for sale (maybe to import it also). When all PINs are sold out, item must be invisible for customers and admin must get mail, that all PINs for item "PIN number for service xy1" are sold.