Saitek X-52 Pro - How can I map the wheel on the throttle?

I use a Virpil joystick with a trim wheel.


I found that the trim wheel just does not move the trim fast enough on some planes where the default is set a lot off centre. So I bound two buttons to this one for the ability to keep it depressed for long travel movement. The trim wheel, which is 28 and 29 on mine, for small adjustments.