Mounting DVD disk in virtual kernel

[vasily postnicov <shamaz.mazum@xxxxxxxxx>]

Hello. Can anybody help me to mount DVD UDF image in vkernel (from DragonFly_RELEASE_2_8 branch of git repo)? I start it as follows:

$ sysctl vm.vkernel_enable=1
$ cd /var/vkernel
$ boot/kernel/kernel -r root.img -c /path/to/udf/image/img.iso -m 100m

Inside vkernel box I cannot either mount image or even read it with dd:

$ mount -t cd9660 /dev/vcd0 /mnt
cd9660: /dev/vcd0: Device not configured
$ dd if=/dev/vcd0 bs=2048
dd: /dev/vcd0: Device not configured

I know, maybe the reason is trivial, but google doesn't give answer. 

With best regards, Vasily.