If I understand you correctly you want to remove the color from the cloths, but keep the rest colored, correct?

The easiest way is to go into the material room and find the image nodes that have the color that is applied to the cloths.  Add a cycles>converter>separate HSV and a cycles>converter>combine HSV nodes. Take the color image map and feed that output into the separate HSV.  Take 2 of the separate outputs (H & V) and connect those into the combine HSV (H &V).  Leave the S output unconnected and on the combine HSV make sure the S value is set to 0 Zero.  Finally take the output of the combine HSV and attach it to where the color image map was going.

What this does is takes any color maps and removes the saturation basically turning anything to a grey scale.  When you render the result will be gray scale with the highlights baked in.  Easy to then tint to the color you want.

If you want to do the tinting in Poser then do the same as above except hook up the S & V together and put a color chip into the input of the H input of the combine HSV.  This will give the same amount of brightness and saturation, but change the color from a red to a blue as an example.  Multi-color maps will be turning into monochrome color, ranging from black to the color of the input chip.  So if you had a Red and Green Flag, it would become a single color such as yellow if that was the input chips value. 

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13