I'm not sure about the Warthog, but the software for my Saitek X52 allowed me to program the throttle as "bands", each of which could simulate a keyboard button press. So, for example: I set the throttle to have 5 "bands". Going from closed throttle to open, they simulated the button presses for reverse, stop and then three forward button presses. Only problem with that setup was that if I moved the throttle from stop to fast speed (2x forward button presses) and then back down to what you think would be slow, I ended up at top speed because that was actually another forward button press. So you'd have to move all the way back down to stop and then up to slow. If that makes sense.
It worked. But in the end I decided it was actually easier for me to just use the keyboard. I think there is a thread around here somewhere that has my old X52 profile in it.