Well, let's try a few... I'm not sure what this will do.
? ? ? ? ? ? ä - the last is a combining diaeresis ... closest I can get, but it's misplaced:(
Edit: Yep, that didn't work:)
Anyway, it definitely looks like a shortcoming of the forum software, there is no need to rationalise it by the rules ... There are places where the characters will help a lot. It won't hurt the rules.