Well the kanji is a big problem. I think i was able to type only few of them. It looks like its not supported which is really funny coz hiragana and katakana (2 japanese alphabets) are allowed. For example 　楽しい works fine. But ur not able to write Japan in kanji 「日本」unless u use the hiragana version「にほん」.

だいすけさん説明してくれませんか。 :-)