Hmmm.. I would think OS should still see it as a new device even if thats the case.

Well I am studing the schematic now, I am not sure I have the "CAP" on Vusb. But I can say this thing works with a USB bootloader no problem. Now does that mean winblows will see it? IDK

I see there are pullups on the data lines. And according to the datasheet, The internal pullups must be disabled. I have been looking at the include file, and I think there are being set.

I am just about to give up on this "pre-configured" answer. After all, it may NOT be the answer for this chip anyway. I will start looking at your solution to see if I can make that work.