Try UltraIso. http://www.ezbsystems.com/enindex.html
That's what I've always used to copy and edit my N3 discs, and I can't see how the D3 ones would be any different. I use UltraIso to make the image and then Nero to burn, but there is a burn option in UltraIso. I bet that would work too. I'll have to try it myself.
If the D3 is similar to the N3 and if you don't want to waste dual layer DVDs, you can make a test DVD on a single layer if you delete all the large POI files. Just look for the files that are several hundred megs in the POI directory, delete them, and then make a new image. It will be less than 4.7 gigs, so you can burn it to a single layer and test. Everything should work except the POI search. I do this all the time when I edit stuff like XM logos so I don't kill $3 dual layers experimenting.