sampler envelope question

Quick question:
When I set a short sample up so the tail of it will loop and sustain, and turn up the release all the way, it will sustain for the proper amount of time if I hold the key down, but if I just tap the key it will not sustain and just cut immediately before the sample can loop. Is there a way to work around this with LFO on the loop points to psuedo time stretch? Or do I just have to adjust my playing and hold the notes down for them to finish ringing out?