creating loop points in a sample for the NN-XT

[speaker]

Im trying to make the tail end of a sample loop infinitely. Doing this with Reason's NN-XT alone is very difficult. So I brought the audio sample into pro tools and found the perfect looping point at the zero crossings but i cannot figure out for the life of me how to set these loop points so that when I re-import the audio file into the NN-XT it identifies the loop points

Like many samplers the NN-XT does in fact have this capability. HOW ON EARTH do you do this in Pro Tools???????????????