Hi, how would I mess around with an instrument’s keyzones so that when I’m holding a key down, the sample starts playing from the beginning, yet when I release the key, the sample starts playing from beginning of startloop, and plays until I kill it?
5414 
In short, You can’t.
You can map a looped sound to the note-on layer in the keyzones, and then you can map a different sound to the note-off layer — this works pretty great for things like sustained guitar string notes, which then need to make some kind of fret noise as the virtual player releases his finger from the string.
However, the note-off layer is only intended for some kind of one-shot sound. Looping is not allowed there, simply because the sound may easily play forever, with no way to stop it except hitting the panic button.
In your example, how do you imagine you would kill the looped section after the note-off has already been sent? By sending a 2nd note-off, or something like that? I think this kind of multi-stage note-off logic could get pretty ugly pretty quickly, no?
You are of course correct. I forgot about the note-off having to be without-loop. D’you think there would be a way of duplicating only the portion of the sample (where the loop starts) onto a secondary sample inside the instrument, and to use that for note-off? I’m guessing it wouldn’t be completely impossible to do that with scripting… I should probably start getting into that. Could be very interesting…
I suppose you could stick the looped portion on it’s own modulation set. Using the Envelope (the multipoint one) with sustain set to zero, you wouldn’t hear the loop until the release stage, during which you turn it back up and of course make whatever shape you want.
(if you feel you must loop the release portion of the envelope,put in mute group to kill it on next note on?)