I think i know what your having issues with there. The two nodes that seem to confuse people are the image node and change range node. flow should look like this texture>image>color2scalar>changerange>material change range is located under nodes>math>changerange. Hope that helped.
Anyone know how to do this? I tried following the zb>xsi pipeline tutorials from zbrushcentral, but it misses out some stuff. For examle it shows the render tree setup, but there are two nodes in it I just can't find anywhere. Help us Obi Wan Kanobi...you're our only hope...