Ok... So to change the functions of the sticks needs some mixes/flight modes...
Have a look at this video...
http://youtu.be/09fe49ply7o
Whilst it is on a 10t it will still work on a dx9 or 18.
Cheers,
Ap
P.s. It won't matter which dx9 you buy... They should all be compatible, I am running the latest version of airwave sw on mine, and it's aok...