When I try to make a custom DVD using Toast, I am not able to see scenes to choose from, only file names on the DVD I want to choose from. How do I choose scenes?
Then I don't know how you can achieve that in Toast. Have you looked at the HELP of Toast?
I would rip the DVD to the HDD, and select parts of it via Handbrake or MPEG Streamclip (for which you need the QuickTime MPEG-2 Playback Component), and then export the scenes from there and then burn them.
But there may be an easier way, maybe MRoogle can help.