I don't think it will fit, the picture looks totally different, not sure what I was thinking>
I found mine because another forum member posted that a dealer had two. They may still sell them or some dealer may have it in stock somewhere or maybe you could make it out of plywood and have seadoo upholstery make the cushion for you...
Part number was 295100083, I believe hlsm.com has it as 295100084....