Okay, I think I misunderstood what you were saying in the first post. I am now assuming you are not talking about elev-flap mix, just the flap function of flaperons. In this case I think you could try setting the flap control to VRA and setting up a flap-flap mix at -100%, using H to turn it on and off. When activated, the flaps should return to their centered position no matter what position VRA is in. If I'm still not getting it right let me know.

Ryan