I found that Body Shop doesn't like layers any more. Even after they're together, it makes the clothes colors off- if I've changed the hues (iirc).
What I did (and I don't know if it does it to that shine layer from the other layers) was once the edits were done in Gimp with the layers, I'd copy the work from Gimp then open it Micsoft Paint and paste the work over it and Save. M-Paint doesn't do layers so BodyShop* seems to copy it well.
I want to open that up and see what's going on but I'm only a recolor/cut-paste in Body Shop so I don't have much experience to help. :(
