Facebook Ignited Infinite Loop Problem

[eluser]programmieraffe[/eluser]
I think the problem is the following:

The facebook-api redirects to "domain.com/welcomeFacebook/?code=878908098&state=98989898". Without clean urls, the "?" is the first and is recognized properly. With clean urls and the rewrite rule (see below), there are two "?"-signs in the URI and so only the first one is recognized as parameter. ("domain.com/index.php?/welcomeFacebook/?code=dsflsadkflks&state=98790898")

Code:

RewriteRule ^(.*)$ index.php?/$1 [L]

I don't have a easy solution right now to make this work, maybe the regular expression should be altered to check for "?" in the url?