Your mower has a fabricated deck, correct? If your mower is the same as the YTH, then this would almost fit, but your mower doesn't have a stamped deck so this wouldn't work anyway: Husqvarna 531 30 96-41 42" Tractor Mulching Kit (HU42)
I looked for a long time, and I couldn't find one that would work, either, so I think the best thing would be to talk to your local Husqvarna dealer.