Update databasetable upon successfull paypal paypment?

[svenn]

Hi guys

I'm working on a site where we plan to sell virtual currency / points etc. So what I need done is for whenever a successful payment / purchase through paypal is completed, I'll need one of our database tables to be updated with the number of points the user purchased..  Is this possible using virtuemart without hacking the corefiles up and down?