Apologies for my noobishness but bare with me

My problem: I authored a DVD with DVD Lab Pro 1.52 which has two VTS sets. each with one half of the movie in. unfortunately i (like an idiot) didnt bother checking the end link for the first VTS so instead of carrying on with the second part it goes back to the main menu.

is there a way i can just change the link without having to reauthor the DVD?

btw i dont have the project files anymore so its a fix or completely rebuilding the thing from scratch

people have mentioned IFOEdit and PGCEdit and DVD Remake Pro but i havent found a single tutorial that tells me how to change the link (if that is what its called)

can anyone help?

thanks