Precision Flight Serial CAT III and Microsoft Flight Simulator 9 (2004) - Manual (Page 7)

Serial CAT III and FS2004 Setup Guide Page 7
ENABLE TRIMS
1. Let us go to the Trims & Steering tab.
2. Enable the Aileron Trim and Rudder Trim and move them left to right and see if they are responding.
AILERON TRIM CALIBRATION
3. Now click on Select button under the Aileron Trim Axis. This should say Set Automatic now.
4. Turn your Aileron Trim knob the way to the Left. Click on the Set left most limit.
5. Turn your Aileron Trim knob all the way to the Right. Click on the Set right most limit.