Minecraft on Mac OSX doesn't Supports the German Ä, Ü, Ö and ß ?!

At the 1.5.2 Version (and the Versions before) I could write the letters ä, ö, ü and ß in the Chat, but since 1.6.2 I couldn't any more. This is totally annoying, because that letters are very often in german words. I thought that this was just a bug of the 1.6.1 but it still was there in 1.6.2 . But the strangest thing was that all of the Windows Users could use that letters... I hope this bug is fixed very soon 🙂