Wow - never saw that doodad before. Some incredible stuff coming out of Poland these days. But as to why it's not 100% compatible... not surprised. That USB to DB9 conversion is logic controlled, so unless you can update its firmware (which I highly doubt they designed it for that), you're going to be SOL buddy! That's a goofy piece of kit you have there. Kinda surprised it works at all. lol
I know there are utilities on Aminet that aid in using PC mice and such, but I'm sure they wouldn't work with your device. Might be worth searching though...