You are correct in that they will both turn the same direction, but this is what you want with ailerons. Look at the diagram I have attached. You will place the pushrods both on the outside of the servos (or the inside as the case may be). Now when you move the ailerons both servos will turn the same direction, moving one aileron up and the other one down. With both aileron servos moving the same direction it's the same identical movement as if you had only one aileron servo moving both ailerons, one side moves up as the other side moves down.

Hope this helps

Ken