Hi Michael, it sounds like you haven't assigned the proper switches on your dx8. To do this, hold the scroll wheel down then power it on. This brings up the system setup screen. Scroll down to Switch select and click on it. This lets you turn on/off and assign the switches on your radio to the proper plug ins on the receiver.
As an example, I'm using the F mode switch for my 3 position switch, so I scroll down to F mode, click the box and scroll to what reciever channel I want to assign which would be Gear since that's what my U channel on the naza is plugged into on my ar8000 receiver. Hope it helps.