CJK input don't seem to work right (although it displays fine once entered). There are special steps you have to take because of the way input works for those languages. Here is the cached version of an old article I read describing how to do it (summary: use the NSTextInput protocol).

http://webcache.googleusercontent.com/search?q=cache:ORe08or...

(It's a bit harder to read because the screenshots weren't cached, but it should still be a good starting point.)