Joomla RS FORM PHP Script

I am trying to integrate Joomla RS Form and Virtuemart by using the mapping tool in RS Form. I manage to let the user choose their own shopper group and the data is added into virtuemart database. But when I try to edit the shopper group in the submission area of RS form and save it, the database in virtuemart doesnt save. I want the database to update after I edit and save the submission.