Alignment off after exporting as Bundler negative-Z

When I’m creating textures I like to manually blend some of the areas myself.  I have a camera pointing right at the model’s face so I like to use a part of the texture from that camera.  I need to manually do this using Gimp because sometimes I only want to use the eyes, or the mouth.  This requires me to create quite a few “single camera” textures, like sometimes from crotch, bust, feet, back of head, etc…  Its different for each scan. 

So what I like is to be able to just create a texture from 1 or 2 cameras and be able to export only the texture file.  It also helps when the rest of the texture is black instead of interpolated colour 'cos then I can see the areas that have come from the actual camera.