In our SSS tests we found, that if you plug in an image map to the "volume 1 colour function" slot, the density is completely black unless you check "repeat x" and "repeat y", but then the UV mapping doesn't match. So KyL had the idea to plug the image map shader into the "volume 1 density function" slot. The UV mapping seems OK, but after numerous tests, I found, that it only reads the black and white information of the image map, but no colour information at all. I tested it by setting the decay to 0 to see, if there is any colour. The volume 1 color was set to grey, and for testing I applied an image map shader with an exaggerated green tinted texture map of my object to the volume density function slot, but the rendered head remained grey. Of course it seems logical, that for density TG only reads b/w information, but so I assume, it's not possible at the moment to apply a correctly placed colour texture to a glass shader, that's set to subsurface scattering?