Camera Connect will allow you to do this and the Easy Connection guide in the wireless instruction manual makes connecting pretty easy. The app will allow adjustment of aperture, ISO and shutter speed in Manual exposure mode as well as touch AF. Manual available below.
Yet it is notoriously unreliable, frequently dropping connection. I need a professional solution, that will function every time.
Don't categorically blame the camera. The next time it happens, check to see to which wireless access point the iPad is connected. The problem is that the iPad will switch wireless networks, if the camera goes idle a some period of time. Smart phones will do the same thing.
Does your iPad have phone service, or is it Wi-Fi onl? Mine is Wi-Fi only, and I have no issues with the IPad switching networks to the phone service wireless data network.