On the simulator DWI (Dance With Intensity) there is a way to just put the kanji in an image and get it to display on the songwheel in DWI. See the readme for instructions on #DISPLAYTITLE and #DISPLAYARTIST, I believe they are.
But for some reason (it would make things a lot easier as far as accommodating songs or artists in foreign characters) Stepmania does not support this. Instead you've gotta do what the two people above said and hope that Stepmania happens to have those characters, which it might not.
__________________  |