I have come to the point where I managed to join a shader definition, made with the EZMat-Generator, into the template plugin code, connected diffuse color with an input node and have it working!  Heyhey! Victoria 3 can have her various materials recolored.

Many thanks Mr. Snarly!!

I have a question now: How I can force a refresh of the document window?  I see the result of my changes only when I go into the material room and select the material. 

Do I need to remove the 'pass' at the end of the code?

Added in edit:

Do I need to restart Poser when I made a change to the plugin or is the latest version read from the folder by pressing 'refresh'?