RE: 12Z mixing for flying wings ??
Apparently, you cannot mix to a virtual channel. To do what you want to do, you'll need to use two mixes for each of the types of trim you want to do, and mix to the channels involved, and not the functions. One way to get extra mixes is to use conditions, so you can activate a condition that gives you the pitch mix when you lower gear. Just use the gear switch to activate the condition.
The other alternative is to manually compensate on the elevator stick.
We will let Futaba know of this difficulty.