If it's the old analog, you are correct in that it will NOT work with a USB adapter. In fact, unless the stick comes with the USB adapter and is designed to use one, you should not ever use a USB adapter on a gameport item. You need to get an actual gameport to USB convertor (around $40 USD I think).
For one the clocks are different, for another you can fry the stick or possibly short something in the motherboard if you just plug a plain-jane gameport-to-USB plug on the end of one.
