Victor Nemechek, product manager for Toast-maker Roxio, has told MacCentral, that the Mac CD-R mastering software will support Apple’s Disc Burner utility once the 5.0.1 update is released “some time in April”.
Toast 5.0.1 will enable both Disc Burner and iTunes to be fully supported when used with Toast's own system extensions.
Toast 4 doesn't work when the current versions of iTunes or Disc Burner are installed. System extensions that enable the Apple software to burn CDs conflict with Toast's own system extensions. Users can create separate extension sets for Toast and for iTunes or Disc Burner; they then must activate the appropriate extension set in order to get their CD-R drives working with the corresponding software.
For more on Roxio’s Toast 5 Titanium, read Macworld’s review.