It soulds like the nipples on the texture do not fall in the same place as the material that is called "nipples". A lot of people design textures for cases when the model is all white. The only ways you can get around this are to either move the nipples on the texture, or do a hue adjust on the texture until you get the color you want. Just make a selection around each nipple, feather it very slightly so it blends into the surrounding area, and then adjust the hue. That should do it.