At long freakin' last: I can input Japanese in Linux! There are so much scattered documentation on the web on how to get it working, and most of it seems to be in Japanese. And, well, I'm still largely a Nihon-go illiterate. So many of the results I was getting from google weren't helping me too much (well, I could still pretend to try to read some forum posts by guessing what certain Kanjis meant).
Watch out world! I can e-mail in multiple languages now!
I'll probably put up a small tutorial of the steps I took to finally get it working soon.