MVC :: How To Modify Generated Membership Functionality

I am using ASP.NET MVC2 (and I am new to MVC).

I created a new MVC2 project and use the SqlMembershipProvider and Forms Authentication but am not using Roles (yet). Each user has additional information associated with them (e.g. Company) which is stored in a different table than the aspnet_* membership tables.

I store an additional small piece of information in the authentication cookie (e.g. CompanyId), and create a custom identity object during the AuthenticateRequest event and this custom identity object exposes the CompanyId as a property. Thus, CompanyId is available in controller actions that has been decorated with [Authorize].

When creating a new user, I now want to create this additional user information (e.g. Company) and associate it with the user. I realize there are many different ways to do this but since I am fresh to MVC I am soliciting advice about the best way to do this - I want to do it in the best "ASP.NET MVC way".

One option would be to change the AccountController's Register action and after a successful call to MembershipService.CreateUser(), do the work to create the additional info in the database. Doing it this way does not require any modification to IMembershipService etc.

Another option would be to modify the IMembershipService interface (add a "company" or "companyName" parameter to the CreateUser() method), then modify AccountMembershipService's implementation of CreateUser() and do the work to create the additional info in the database there.

And yet another option would be to leave IMembershipService alone and instead create my own IMyMembershipService and MyAccountMembershipService and use those.