Visibility condition for "Parking Brake"? (Solved)

I am working on converting some AI aircraft from FS9 to FSX. The problem that I am running into is that there are objects attached (Airstairs etc) that I don't want to delete. I am using the visibility condition Prop0_still right now and it makes the objects disappear once the engine starts, but the objects are still visible during pushback. Is there a visibility condition that I can use to make the objects disappear as soon as pushback is started such as something related to the parking brake being released? BTW I am very poor at XML coding so telling me to write a custom condition is no help at all. LOL
With some older code from TGibson and using variables from WaterRudder_Rev_Vis I got it to work. The Airstairs now disappear as soom as the aircraft starts pushing back.

           <Code> (A:SIM ON GROUND, bool) (A:VELOCITY BODY Z, knots) 0 == and
       if{ 1 } els{ 0 } </Code>