Comment 5 for bug 773512

You mean this letter: " ß "?
Because on my case it works fine. But I don't have an "out of the box" configuration because I had some problems as well to compose few letter, like " ć " and I changed the configuration list by adding this in my .profile:
export GTK_IM_MODULE="xim"

And now everything is working fine, except that I've to used shift + right super.