Not using multibox.

Prog.Mix 6
Rud>Aux4
Pos 0 +100%
+100%
Pos 1 0%
0%

Bottom right of the screen you have Ail, Ger, Rud, Mix
Pos1 set on Ger


Butchered this pic from the manual, so just imagine it with the input from above.
It shows the Gear posistion on the bottom and throws at position 0.