It works fine but it does require you to save at least two shaders - by virtue of being a Reference shader, it is a multiple shader solution.

For example, I import M3 and in the texture room I modify the Arm texture so the shininess and bump are what they should be. The next step is to save the Arm channel as a new shader - this will become the master skin texture. Now, using the M3 master shader, I can then subscribe to the Arm texture using the Reference Shader for most or all of the other channels also. 

To save and reuse this work, you do need to save and the both shaders.  I'll save the M3 shader into my browser as a M3 Master and also save the M3 Skin texture. Reusing them requires dragging both shaders into a new document with an M3 Character.

Obviously, all the shading domains need to match so this shader can't be repurposed for the Space Shuttle. ;-)