Here are some general suggestions which often helps when one or more sticks are not recognized:
- Make sure you don't have any other joysticks/controllers connected, that might cause a conflict.
- If connecting via USB, make sure you uninstall vJoy and Smartpropoplus if you have them. Their driver messes with things when connecting via USB.
- Make sure you have "Heli" selected as model type on your radio. ("Plane" generally doesn't work very well).
- Perhaps you can remap the output channels (in the menu of the transmitter) so that it sends to another channel.
If none of the above works you could try to connect an ordinary 3.5mm audio cable from the trainer port of the transmitter to the audio-in (or mic-in) jack of your computer, along with a software called Smartpropoplus (Windows only).
http://www.smartpropoplus.com/site/
There is more info on that in the Spektrum setup tips document: