Sorrys chaps, this one slipped me by!
You need to do a search for an fbml app (facebook markup language), then you can either fill the relevant screen with html code, or simply an image set to the correct size to fill the relevant frame (html would be nicer, but an image is so much easier).
Have a look, if you get stuck drop me a message. I think I still have a template which I set to the right size to fill the area.
Facebook.com/floors2show