Asp.Net Security Forms Authentication

Question

Hi,
      For my application I am using ASP.Net 2.0 Forms Authentication. Asp.net has given lot of tables and Stored Procedures for this. And we can use only the controls inside Membership API for registering user, login etc. But I want to create my own Registration component with some extra fields, but want to use the same tables which are created using aspnet_regsql.exe. Can I do this like this? If so can anybody help me to continue.
Thanks in advance
Derence