If you have the 7C FASST transmitter, you can do both. You use the Flaperon function for dual aileron servos, and the Ailevator function for dual elevator servos.

If you have a 7C transmitter on the 72 MHz band, it has the Flaperon function only. To get dual elevators, you use a p-mix, but you won't have trim on the slaved channel.