Here’s an article on getting Japanese running on FreeBSD. I’m REALLY glad the author took the time to document what he did since I find the process frustrating too. It’s bad enough that the path to UNIX tends to be unfortunately a little obscure. Even worse is when you try to multilingualize it since to start off all the best information will tend to be in the target language.
But the article above explains it in English for English speakers trying to Japanese enable their environment.