event, yer shader renders well, however use of diffuse + specular = 11 violates fresnel's law. it may be possible to modify this with fresnel shader.  redviper also posted freebie soap shader at sharecg (The Easy shader3).  goes to page with nudie pix.  maybe if you use p-node, y-direction can cut off foam, but it's camera-specific.  in character texmap, v-direction would cut off leg form, whilst u-direction cuts off arm foam.