Customizing WHMCS provisioning

Hey - I currently use Gforms and have a really nice layout for signup and allows me to pass the template_id in the array on the wpmu reg

Can WHMCS provisioning be customized at all to allow me to collect the templateid in customer details so when they purchase, etc, it pulls blog name, description, etc?

Or would i have to hack it apart and kill the probability of updates?