Philosopher - 3:24 pm on Feb 18, 2009 (gmt 0)

Maybe the problem is that ga doesnt see a different between /? and /.

Almost certainly the problem. I just ran into this with a client's site. The contact form posted to itself so I tried to differentiate the two URLs for the purpose of defining the goal by tacking on a ? to the action. While the browser shows the URL with the ? tacked on, GA does not. If you pull up the top content report, it shows no hits to the ? version even though there have been conversions.

Can you add some extra info to the URL? possibly instead of it returning to /contact-us/? it could return to /contact-us/?status=done

It worked in my case.