If you have Nero Vision, elect to make a DVD Movie, then load the MPEG as the first title. You can now load the VOB files and either merge them as a second title or optionally merge everything into one big title, so that the cartoon plays and is immediately followed by the movie.
Thanks and I have tried this and I have not burnt it yet but the menu for the movie seems to be gone.
I don't think keeping the original title menu for the movie is possible - it would be feasible to create a new menu with DVDAuthor GUI and add both titles to a new compilation.