I am building a Facebook Connect application that runs inside a Google gadget. Being a gadget means that the application runs inside an iframe. Inside the application, there is a form that allows registered users to post comments. The submission is made using AJAX, but I get the same results with a normal form. The problem is that I need to get the user's facebook id. In Firefox, it works fine, but on Internet Explorer 7, I get the following error:

 'A session key is required for calling this method'

I believe that this is due to the way IE handles third-party cookies, because if I go to Internet options / Privacy / Advanced, and check Override automatic cookie handling and accept all cookies, it works fine. I cannot pass the Facebook id from the javascript, because anyone could tamper it.

EDIT: If I open the content of the iframe directly, the app works fine. The problem is really due to the IFRAME and IE security model.

What am I doing something wrong? How can I work around this problem?