I have a Rekluse RMS125 z-Start Clutch kit from my 2001 FC550. It states on the cover of installation guide "Husaberg 350, 400, 500 (1989-2002).
I have a spare inter hub that's already milled down at the spring posts.
Mars
KTM 250 SX 2010, 2013
Husaberg FC550 2001