How can I set the ailerons to act as spoliers when elevator move up 100%? Already have the ailerons set up as flaperons (using channel 6), but how can I mix them with the elevator so when I pull hard up they (both ailerons) would flip up?

Is this possible with the 6EX?

You can't do what you want to do. It would take a minimum of 2 pmix's, and the 6EXA only has one free mixer. Just having elevator mix to flap would only move one of the flaperons, since only one surface is on the flap channel. You need more radio to do what you want to do.