How do you use advanced editing functions?

I haven't found any documentation for these functions. But they basically do what they are called:

- Pitchbend bends the pitch (in units that I don't understand) like the pitchwheel of a synth.

- Modulation modulates the sound, depending on how this modulation is assigned. Again, like the modulation wheel of a synth. Most of the time it's a kind of vibrato.

- Sustain is the sustain pedal - it only has the values 1 and 0. As long as it's 1, the pedal is down, with 0 it's up.

You're right, these controls are clumsy to work with. Sometimes the wheels and the pedal of your keyboard will do the job. Try it out!

As for the character of the piano - you definitely wouldn't use those controles to alter it. If they don't sound realistic, they're bad samples (although I find them rather convincing). You can manipulate the cutoff and release parameters of the piano if you click the little pencil icon next to the generator menu in the Info window (under the Details triangle). Adding some reverb might also soften the release a bit, though I wouldn't use too much of it.