Hi,
I use the same controller.
I suppose what you are calling a "Z-Buttton" is actually Z-Axis, i.e. trigger buttons. Am I right?
If so, then it is called "Throttle" axis in WOFF key settings.
However you will also had to invert it and key settings program doesn't allow it. Additionally I had a hard time making settings program recognize any axis during binding.
So, instead I just opened
C:\Users\your profile\AppData\Roaming\OBD_Games\OBDWW1 Over Flanders Fields\WOFFKeys.xcain the notepad and edited it manually.
Here what it looks like for me now:
<Device Type="Microsoft Xbox 360 Controller">
<GameMode Name="Player">
... some lines skipped ...
<Axis ID="
Throttle" Action="
Set_Yaw" Scale="
-64" Nullzone="0" FriendlyDesc="
Yaw Control (Rudder)" Category="AircraftControl" P4Use="y"/>[
<Axis ID="
Rudder"
Action="" Scale="64" Nullzone="0"
FriendlyDesc="" Category="AircraftControl" P4Use="y"/>
I set Action="Set_Yaw" for an axis with ID="Throttle" (i.e. our Z-Axis) and additionally I set Scale="-64" to make it inverted.
At the same time I removed the action from the axis called "Rudder". Most likely this is not needed, but I did it just to make sure there are no conflicts.