I’ve tested out this migration process on one of my pages, and it works fine. Here’s what you have to do to make it work with SFC if you were not using a Fan Page already (note, if you were using a Fan Page already, then you’re done and must change nothing at all).
1. Create a new Fan Page in the Brands/Product -> App category.
2. Give it the same name as your App (exactly the same, mind you).
3. Set up the new fan page however you like. Take its ID number and put that into SFC, then use the Manual publisher to fill out the wall with some of the older posts (the wall content will NOT be migrated when you do the migration).
4. When you visit your app’s wall, you’ll get the migration message (eventually). You can use this to migrate all the people who have liked your application to having liked the new Fan Page. If you used a vanity URL, this will transfer also *if* you don’t put a vanity URL on the Fan Page.
After you’ve migrated the likes and changed SFC to be publishing to the Page, you can continue on as normal. Nothing else about SFC changes. Since Facebook will be eliminating App Profile Walls entirely in February, I’ll be removing support for them from SFC entirely before then. Expect that change to be in SFC 1.3.