If you have a copy of FO3 I would find the tile your interested in in its GECK then Cross Check to see if the textures for it have made it into FNV. If so You then can use those textures to retexture the Rusted vault section.
Many of the Vault tiles use the same Textures and, all you would need to do is find all the ones you need and, replace the file paths in nifscope or, use Texture sets in the GECK. (That is if they still exist in FNV.) If not your going to have to retexture the peace yourself as, using FO3 assets are, out of the question.
good luck
cev