I am trying to setup FBA by using a provider that inherits from the MembershipProvider and has to plug-in to the existing authentication provider.  I got it to show the Access Denied (confirmed by checking the trace) and the login does return a true means it is authenticating against the db, however, I am not able to pull up the user account in the site collection administrators, simple get user not found.

Any idea on what I need to do here?

thanks.