Hello,
I have got a problem with zSphere and/or Transpose Master. It is working fine with default Tools like the dog but not with imported Tools. With my own Tools, once i created the zSphere structure and i move one of the zSphere element, all the mesh polygons disappear but a few around the zSpheres. Is it only me or did I miss something?
Does your mesh have a lot of triangles at its lowest sub-division level (for example, from using Decimation Master)? If so, then that will be what is causing the problem. Tris do not work well with zsphere rigging. You will have to use the Transpose line to pose your model (you can still use Transpose Master).
I have tried at the lowest possible sub-division level, but I still get the same problem. Now the tool is disappearing completely.
I´d try with the Joseph Drust method in the First video here
http://www.zbrushcentral.com/showthread.php?183363-Joseph-Drust-Riot-Games-Recap-Part-1