Well, that's interesting! I wish I was aware of a comprehensive tutorial on the Cycles hair nodes in SuperFly. Looking at Blender/Cycles forums shows me that intercept should return a float with 0 for the hair root and 1 for the tip... Aaaand that's exactly what it says in the Poser Manual too, but without any examples... Uuuntil I look in the libraries under SuperFly Advanced Hair and discover the Hair Compound node examples with multiple Hair BSDF nodes.

What you need to do with your transmap is multiply it by the HairInfo:Intercept output before you plug that into the Transparency input. Unfortunately, Intercept will be 0 at the root, which should be opaque, and 1 at the tip, which should be transparent. That's OK for what you have, with the PhysicalSurface TransparencyMode set to Transparent, but the brow transmap will almost certainly be an opacity map, with black where there's no brow, and white (opaque) where the eyebrows should be.

So, you'll need to change the TransparencyMode to Opaque, and multiply the transmap (Opacity map) with 1 - Intercept. I see that the Advanced Hair shader examples with Poser 11 use a Bias math node so that the tip transparency does not come on linearly, but delays its onset until closer to the tip.

I've grown some quick and dirty brows on the eyeBrow actor of a conformed V4 figure (set to outline mode to highlight the brow guide hairs - Poser doesn't want to display them populated, because I'm running a RayTrace Preview).

Here's the partially completed RayTrace:

I keep having to bump up the hair density to get it to render dark enough to match transmapped brows. Here's my first draft of your PhysicalSurface setup with transmap:

As you can see from the preview, the transmap doesn't gate the specular output, so you need to feed the opacity map into the Specular colour, as well:

Et, voilà!

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