You will need to enable CAM support in the kernel.  Your kernel
configuation should include:
    for SCSI CD/DVD devices:
	device scbus
	device cd
	device pass
    for ATA CD/DVD devices you will need the above, plus:
	device atapicam

You will also want to make the CD devices world read- and writable.
In /etc/devfs.rules, add the following:
	[system=10]
	add path 'acd*' mode 0666
	add path 'cd*' mode 0666
	add path 'pass*' mode 0666
	add path 'xpt*' mode 0666