Link'ing to z3d:
Keeping IVF on model

Create a new folder, on your desktop, name it whatever you want. Extract all textures from your : modelname.txd to : foldername
Put the : modelname.z3d from archyve in your : foldername, run zmodeler 2.x.x and follow the image.
After that simple open : modelname.z3d from your : foldername and start editing.