Japanese character issues

We have someone developing a chat client in flash that connects to an FMS server. Typing works fine in English, but if you try to type Japanese, it spits the characters out one at a time into the chat window after pressing return. This makes chat very difficult and extremely long for Japanese folks:
L
I
K
E

T
H
I
S

Above is how Japanese would show up. I should mention that this happens only on OSX and not Windows. Anybody have any ideas on how to fix this? Many thanks!