can you check if the controller can communicate with the iPad?
In order to do so please download the free application “midi wrench” and see if the controller is sending midi signals.
As the controller is natively supported it should work via plug and play.
If the controller is not communicating at all please see if the cable is working.
Actually, when i plug the midi, ipad starts charging, stops, and starts charging again. The midi lights starts on and off constantly. I made a test on an iphone 4s and works perfectly