To reverse the servo you need to exchange the two of the three (leave the center lead as is) leads going to the potentiometer and the two connections to the motor. Unfortunately, the newer servos often have these two leads mounted right on the PC board to you have to either unsolder them and rotate the motor 180 degrees or cut the pc traces to them and solder jumpers around them to the opposite terminal. If you are lucky, you might find a Futaba servo with the same power and movement and use it on one of the elevator halves as Futaba and Hitec move in opposite directions with the same input. Check with Hitec, they may have a reversed servo available on special order.