amazing distortion with a digitech?

I've got one of those new Digitech GNX2s. Its got great versatility apparently, but im having a hrad time getting a nice meaty, sound, with lots of sustain. it has capabilities of simulating various amps and such and then combining them, but i have a hard time doing that. anyone know any EQ settings or compression setting that would get me the distortion of say steve vai or joe satriani?

also, what kind of pickups do they use (that could be the problem, i have ibanez stocks)?

thanks for your time
shredda