This is a bit of an unrelated question, but it is pertained to BD-Rebuilder. Is it possible with the program to replace the main video, but keep the menus and everything else in tact?
Yes, if you’re careful. Put the .x24 file in the same folder as the working files, and create a .CMD (batch file) to rename it to the main one and remove the main file. If 00000.mpls is the main file it’d look something like this:
del VID_00000.AVS.264
ren replacementfile.264 VID_00000.AVS.264
Run BD rebuilder, wait for the main movie to extract, then run the CMD file you made. You must do it immediately after it has demuxed and before it has a chance to begin remuxing the file.