I've seen that kanji on WP and a couple of other Japanese sites, but I've never been able to find any official sources to confirm it (I don't believe it's ever appeared in a game or on an album), so I don't necessarily trust that it isn't just something that someone made up and other sites copied. The closest I've been able to find is that "KENNY西田" is allegedly given in
the Psycho Soldier strategy guide, though I haven't personally seen the original material to verify it.