From what i know.. is you import a base mesh from maya into ZB then divided the low mesh so that you ahve more geo to sculpt.

Once you have your model scuplted to the level of detail you want you export your low base mesh back into maya then make your displacement maps from the high res sculpt in ZB then add them to you base mesh back in maya.

I have yet to play around much with getting the model back in maya as i've been focusing on sculpting the low base mesh in ZB right now thats my next stage for me to get good at.