Insert checkboxlist selected values into sql table using createuser wizard

Hi,
I am using CreateUserWizard control where I collect personal information from the user on the first step (ie. name, address, tel, mobile etc) then on the second step I collect information for membership service (ie. user name, password, email etc). When user clicks Create button, information is sent to two different tables in the same database. Everything works fine but one.
In the first step where I collect personal information, I also collect details about Interest which is a CheckBoxList (CheckBoxList is getting values from Interests table: 1-White, 2-Green, 3-Brown, 4-Maroon, 5-Yellow).
What I want to do is, when client selects his itnerest categories and clicks Create button, to send selected values from CheckBoxList into the third table called Categories. I want values to be registered into the CatCode column in Interests table as comma delimited. For example: if client ...