I have no idea what you're talking about...
is it like the "sliders" mode you get with ableton Live? Or do you want the pads to act as individual toggles? Is that what you mean by "sustain mode"?
You'll need to describe this a lot more, but what I *can* tell you is that there are no "objects" for that type of thing - you're looking for something that is very close to the core of Max; old-school midi transformation, which it does in its sleep, more or less.