The meshbox figures are built with one UV map. When I load another Mesbox poser figure into C6, it loads the texture onto the figure with a gray multiplier in the shader. This washes out the texture almost entirely. Perhaps this is what's happening to you? In your files there should be a texture map. If not, it might be in those other files you have.
C6 doesn't see the material zones of the meshbox figures. Poser7 shows some that just aren't there in C6. I was planning to create my own.