Loading provider from web.config

I have a custom membership provider (SqlMembershipProvider) which I need to implement but am having a problem with the Initialize() method. The problem is, I don't know how to instantiate the SqlMembershipProvider so that the Initialize() method is called with the NameValueCollection object already loaded. When I used CreateUserWizard with the SqlMembershipProvider, it would call Initialize() on the provider and give it a NameValueCollection of web.config values for the provider. When a new user is created in the database, they need to be associated with an existing id which is gathered be ...