If you are using Poser 5, 6, or 7, here is another way.  Connect the "Bump" to the "Image Map" in the same manner that you connect the "Diffuse_Color" to the "Image Map".  You will, no doubt, have to adjust the "Bump" setting to something lower.  This might be considered unorthodox, but what the heck,  it seems to work just fine for me.