Well, that’ll lose quality no matter what, and you’ll need to be sure it keeps Blu-Ray conformity. I think I usually use meGUI for that, but I’m always encoding from a lossless AVI file, never from h264 to slightly smaller h264. Some other members here would probably be more help than myself on that front.
Did over burning not work? I figured at worst you’d lose some of the end credits that way…