iFrames apps and cookies

I’d like to make my Facebook app in an iframe, for various reasons (faster loading time, full AJAX with Rails helpers) outlined here:
http://www.ccheever.com/blog/?p=10

To get this to work, though, I need to bypass Facebooker’s default authentication mechanisms, because the authentication params are only visible on the first request from Facebook and need to be cached afterwards.

The obvious solution is to store the user’s Facebook session in the session, but this approach doesn’t work in Safari: it won’t let iframes from an external domain set cookies. Has anyone found a solution?

Ouch. That’s painful. You can’t even set a cookie for your own requests? I’ve worked on an iFrame application for Facebook and we were able to use use Safari and keep a session.

I’m poking around the same issue. The best solution I’ve found so far is here:

http://wcrawford.org/2007/08/29/revisited-faceb…

but I’m still looking for some other ways to do it.