Facebook C# SDK - callback on initial iframe app authorization?

I'm working with the Facebook C# SDK on codeplex on a simple MVC 3 iframe application. When a user first authorizes my application I need to store the user's information to my data store - where/how would I do this? Can I redirect the user to a specified action or something on first authorization?

(I'm using the [CanvasAuthorize] attrrib开发者_运维技巧ute to wrap my controllers in which FB information needs to be retrieved.)