How do I implement custom role authorization with ADFS in ASP.Net MVC2?

Question

I'm pretty new with ADFS and and Custom Role authorization so any help (and a lot of patience) would be greatly appreciated.

I'm trying to set up ADFS with custom authorization. I have the ADFS set up to return me a claim, from there I can get a username from the name token. However, I already have an existing roles table which I need to map up to the username from the token and set the session object to reflect his roles?

I guess what I'm very confused about (besides what seems like everything right now) is when the claim comes back, what controller is hit to process the token?

Before changing my app to use ADFS authentication, it would:
1) hit the AccountController,
2)validate the user, and
3)set the Asp.net session to store the users info.

Now that I'm using ADFS, it seems to authenticate the user, and then populate the session without me knowing where to intercept and put in custom roles code?

Can someone offer some direction?