DVDSP kan nu bränna DL media om du har DVDSP 3.0.2 och 10.3.6
http://www.info.apple.com/kbnum/n93962.
Improved Double-Layer Compatibility
DVD Studio Pro 3.0.2, together with Mac OS X v10.3.6 or later, now support burning and reading from double-layer DVD recorders and media (DVD+R DL). DVD+R DL media makes it possible for you to store nearly twice as much data on a single-sided DVD (8.54 GB) compared to standard DVDs (4.7 GB).
DVD+R DL media makes it possible to burn a dual-layer project to a disc, with the project's dual-layer break point controlling when the double-layer drive switches from the first to the second layer.
To burn dual-layer projects to your double-layer drive, your system must have:
DVD Studio Pro 3.0.2
Mac OS X v10.3.6 or later
The latest updates for your double-layer DVD recorder from your drive's manufacturer.