Little bit late to this discussion but just saw it and was wondering about what Vometia said; can you not use Texmod to load the new textures rather than repack them or is it the actual model you're editing? I did some basic swaps with Texmod to reduce how silver the eyes were after the ritual and I can change colours of gear too.
However I'm not sure if it's possible to swap models with this, for example could I swap the appearance of two different types of armour? If so could I swap the appearance of a helmet with the appearance of my character's head? I did try some messing to swap armour but it wasn't successful even though I extracted the three textures for it. Not sure if this sort of question is allowed on this forum though...
