You don't need to reverse anything when using the Cortex. It knows from the setup procedure what direction to move the controls to stabilise the model. If you wanted to, you can plug each elevator and each canard in to a different Cortex output and still have one stabilised channel left for the rudder

Or, if you wanted to use a vector pipe, you could have each elevon plugged in to an output, the vector pipe pitch and yaw servos into 2 more outputs and the rudder in to the last available channel. The Cortex really is very flexible.