Without having that particular material, i can't do much.

But i tried to do some drawing to explain much.

The highlighted nodes are those i added.
You only have to take into account the nodes that are plugged into the Poser surface. Leave all the rest alone. You have 5 nodes plugged into the Poser surface, so we'll add 5 blender nodes.

1. For the diffuse. If you don't want the overlay map to be altered by the blue diffuse color you have here, turn the diffuse color into white, and put the blue into the input2 of the blender node.

2. I put black into the input1 so the overlay will not be altered by the color you have in the ambient color.

3. Simple here.

4. I put white in the alternate_diffuse and black in the input1 so the overlay will not be affected by this, only the skin.

5. Simple here.

I hope it helps. I'm far to be the perfect drawer LOL
But i can't do much more because i have not this material. If it's not a commercial one, you could send me the material if you want me to plug the right things in the right places for you, or if you can't follow my little composition :)

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