Nick, are you suggesting that for debugging, to see if it works then? Because that doesn't solve how to fix it in terms of automation.
For a debugging method that will be more closer to seeing if things work in automated test is to run your code (line by line) via an interactive/interpreter session rather than as a test script within your test framework. This is easiest if coding in Python, Ruby, PHP, Perl. It's harder to do via Java, .NET since those don't natively offer an interactive shell.
Rami, what happens if you issue the command to perform login again when run via RemoteWebDriver. Wondering if Selenium will open up the Facebook login page again for you to login, or if it will know that an existing login has occurred and close the popup and refresh main page accordingly to account for login.
Your problem, assuming login is successful, seems to deal with some issue transferring the login session from FB back to the main site.
I haven't seen this problem at our place for automation, but I've witnessed similar behavior before at Groupon.com for manual use (not testing, I'm a Groupon user). When I login (or already logged in since I keep my FB cookie in browser most times), Groupon doesn't get the FB session correctly and still thinks I'm not logged in. Have to refresh multiple times or try the login from a different Groupon page for it to recognize that I should already be logged in (to FB that is). FB Connect solution for 3rd parties isn't perfect, or it might depend on how the 3rd party integrates it into their site, as some sites work well, and some don't (like Groupon).