Incremental CDR backups

[Paul M Foster <paulf@quillandmouse.com>]

I'm having difficulty burning incremental CDR backups. (Using Debian
3.0r1/testing.) They burn fine, but when I mount the CD after the second
and subsequent backups, all I can see is the original session.

Here are the commands I give Linux:

(First burn)

mkisofs -r -o /tmp/cdimage /home/paulf/cdrom
cdrecord -v -multi speed=4 dev=0,0,0 -data /tmp/cdimage

(Second burn, after creating a new bunch of stuff to backup)

NEXTTRACK=`cdrecord -msinfo dev=0,0,0`
mkisofs -r -o /tmp/cdimage -C $NEXTTRACK -M /dev/cdrom /home/paulf/cdrom
cdrecord -v -multi speed=4 dev=0,0,0 -data /tmp/cdimage

According to the CD-Writing-HOWTO and the README.multi doc file from the 
cdrecord disto, this should do it. But all I see is the original session 
when I mount the CD. (And no, I don't want to do this with a GUI, 
thanks.)

Anyone have some expertise they can lend here?

Paul