Why does zbrush replace materials in keyshot?

[bobKotlinski]

I have sent my subtools to Keyshot for texturing and rendering. When I update a mesh in zBrush, and hit BPR to send it back to Keyshot, all of my carefully constructed materials get replaced with the zBrush red clay, and all my Keyshot materials get wiped out! What am I doing wrong?
Please help!