Oh, now read your post more carefully and saw that you mention transparency mapping... Anyway, try this: Copy your figure into 3DS and remove ears and nose. Import the original figure, apply the translucency. Import the second head into the same coordinates, check Solid when Boolean rendering. Make it smaller by 0.5% or even less - 99,5 or 99,7 % in all three directions. Yes, you can enter decimal values. You'll get (at least in theory) subsurface scattering. The only problem is that the second head will have to have either flat colour texture or you'll have to remap it if you want the Poser texture, as the mapping will certainly be off.

-- erlik