Thanks millighost, I hadn't really examined the prop file before. I see the shaderNodeParm channels now. If I'd thought about it I would have realised the need for these, so that Poser can key into the animation process.

Since what I need is just for the material settings to leave the animation stuff untouched, I guess the good old deprecated MAT pose is the way to go for this. I was hoping to be able to distribute something less messy, but hey.