Need help, Rudder to Elev mix with 9C
 

Trying to mix in up-elevator when I use rudder so that knife edge doesn't pull to the belly.

It seems to be simple enough but there must be something I'm missing.
I go to program mix 1 under the advanced menu. I put the rudder as the master and the elevator as the slave, then I tell it how much I want to try -7, +7. Offset is 0. Mix is on. I tried the Link on and off (no change). Trim is off. Switch is throttle, but that shouldn't matter because I have position as "null" because I want it continuously on.

When I test - I move the Rudder back and forth, but no movement in elevator.
What am I missing?

Thanks for any help.