I think if you De-PBOed the Data and Data 3D files and replaced the original .p3d, paa and pacs with your files. But kept the same file names i think it would work. Because you use the same file names, the game will think its using the BIS models and textures.
Then if you PBO the De-PBOed Data and Data 3D files into PBO files, and overwrite the originals.
Warning
This may or may not activate fade because you have edited the game files, but im not fully sure what activates fade, so it might not.
If it does, don't blame me, but if i was trying to do what you want, thats what i would do.