I'm not sure if this belongs here, or in the re-author section.

I'm looking to backup a 2 disc set, both discs have different special features.
Disc one has the regular movie, disc 2 has the director's cut.

I'm looking to backup disc 1 (b/c of the extras), but with the director's cut edition. and not having to reauthor the entire menu.

The main movie on d1 is only 15 chapters, and 30min less. the director's cut has 18 chapters and is obviously 30min longer.

I know I can't just replace the vob set (main movie) with the other main movie set, and have it work.

is there any mix of programs that i might be able to use to "update" the ifo to match the new vob set? or replace/add some lines to do so, that keeps everything else (other extras) there?