Writing DVD-R Double Layer

[Marcus Fellinger <mailings@felliweb.de>]

I have BENQ DW1640 burner using firmware BSLB. When trying to write
DVD-R Double Layer media with k3b, I get the following message:

:-( /dev/hdc: media is not recognized as recordable DVD: 10015

The growisofs command used is

/usr/bin/growisofs -Z /dev/hdc=/dev/fd/0 -use-the-force-luke=notray
-use-the-force-luke=tty -use-the-force-luke=break:2082944
-use-the-force-luke=dummy -dvd-compat -speed=4

>From looking at source of growisofs.c and growisofs_mmc.cpp, it appears
that growisofs does not support DVD-R DL. Is that correct?

Any ideas when that support is going to appear? Pointers on where to
find the necessary information, so I could implement it?

Marcus