[Serusers] Ser and Astcc

Hi all, At this moment, I want to setup a prepaid application using astcc and using multiple asterisk b2bua for pstn gateway. Even though, there have some discussion about prepaid application on ser, yet, I'm not smart enough to make it work just base on that. I have successfully installed asterisk, astcc and ser. What I'm thinking is to create a new table which aggregate everything from both subscriber table in ser and cards table in astcc, and then modify the username and password field (ser) to number and pin of cards table. Am i doing wrong? Is any others elegant approaches to make my prepaid work? I need yours valuable input. Thanks Seong