Does your Sidewinder have a twist function on the stick?
If so, you should be able to map the twist just like on Xybots.

You might need to tweak the analog settings a bit to get it to work properly.
Degenatrons posted these analog settings for use with a rotary joystick-type setup.

They are easy to overlook, but make a huge difference.
This thread on the KADE forums also has info on optical rotary game settings.
Also forgot to mention earlier, but some rotary games also have alternate ROM versions (ikarjpb, ikari3, etc.) that turn you to face the direction that you push the joystick.
Scott