Hello. My name is***** will assist you with your question.
The first thing I'll alert you to is the page for the software for the 3-D Pro. If you don't have the software install for the joystick, I would suggest downloading it from this page and then resuming getting it to work with flight simulator 3. Here is the link.
Actually, use this link instead – it will take you directly to the software download page:
If that doesn't help, please let me know what exactly happens – do you get the software installed? Does it have any effect on flight simulator 3? Does it work with other games?