First of all I want to say that BTC support was released practically untested, as the user who provided the information about BTC extension never replied to the request to verify the suggested code.Hmm, I never received any request... the last email I received from you was this one: http://lists.debian.org/cdwrite/2004/cdwrite-200404/msg00005.html
I've sent you one off-list with download instructions. But never mind...
In any case, I haven't had a chance to try to set a DVD+R disc to DVD-ROM book type, but changing the book type of DVD+RW and DVD-RW discs works fine, after correcting a minor typo:
As you might have noticed another user can't even to btc()... Is there any data on which firmwares support this? A.