I have managed to produce something akin to your problem, but I can't get anything as bad - so have no idea if these comments will be relevant or helpful.

The head on the right was exported from Poser with the "Brows Gone" morph set at 0.010. This meant the meshes for the brows were sunk into the head mesh slightly. When rendered in Bryce with a transmap applied, there is a thin line of see-through surrounding the brow.

The head on the left was exported from Poser with the "Brows Gone" morph set at -0.020. This meant the meshes for the brows were mostly in front of the head mesh. When rendered in Bryce with a transmap applied, there is barely any see-through visible around the brow.

If your problem is related to this, the workaround is to ensure the brow meshes don't intersect with the head mesh. Hopefully this is possible without having the brows appear to be obviously floating in mid air.