Are you using G2 or G3 characters?
If G3 the just export to Photoshop (or equivalent) and re-color/re-draw what you need.
If G2 then you should be able to use the render style to change the colors.
I also have products in the RL MarketPlace (search EZColors) that do the job very easily for G2 characters also.
Jeff
Get my Plugin Manager and TaskNotes plugins for iClone.
Check out EZColors and Other products for CTA/CA. EZColors: the easy way to change Render Styled (RS) colors!
See my CTA Tutorials on the YouTube channel CTAStepByStep