I've been having similar tribulations using a Korg Triton Extreme 61 keyboard as a controller. After a bit of research, I learned that you can set one of the two switches above the joystick to lock the joystick's last position. This may not be ideal, but it allows me to control GPO from the TE.
If your Edirol doesn't have locking toggle switches, I recommend you look into Novation's SL keyboard controllers. They have an amazing feel (if hammer action isn't your thing), and the Joystick controller (which is sort of trackball shaped) can be sprung or unsprung on its Y axis to behave like a mod wheel; though I find this even nicer than a wheel when controlling dynamics.
The Novation SL keyboards also have two backlit 144-character LCD screens, 64 assignable knobs, buttons and sliders, plus 8 velocity-sensitive trigger pads.
If you really want wheels, I would recommend the M-Audio Axiom keyboards, which are very reasonably priced, and have 32 assignable knobs, buttons and sliders, plus 8 velocity-sensitive trigger pads.
I've heard good things about CME controllers too, but I have never tried them, so I'll leave that report for someone else.