The elevator to flap mix is to be assigned to the MIX switch (back right hand side), then set the pos 1 values as needed.

Elevator to Flap Mixing
Move the roller until ELE->FLP M is highlighted, and press down on the roller to enter the function. Rotate the roller until MIX is highlighted; press down on the roller to move the shaded box under MIX to the top or Pos 1. Rotate the roller until DN is highlighted next to Pos1. Press down on the roller, and rotate the roller until you get to about 35 percent. If the flaps go down with down elevator, reverse the value from +35 to –35 or vice versa. Press the roller again after you have finished setting the DN percentage, and then move the roller to the right so that UP is selected and press down on the roller. Rotate the roller until you get to about 35 percent. If the flaps go up, reverse the value from +35 to –35 or vice versa. This will give you flaps mixed to the elevator for tight loops, etc.

To reverse the direction of the flaps as ailerons reverse the value of the mix from a + to a - value or vice versa as needed.