just one thing:
the above command will copy the complete system, that is also all data;swap etc.
when using it with a working OS-system, the result might become huge.
to the OP and his purpose i`d propose creating a separate partition, running a fresh install, configuring the system and after that running the lh_config-command to create the copy.
If you want a copy of your working system, you could try moving all the private data
on a separate partition, running the the copy with live-helper and then moving the private data back ( i dont know if one would be able putting the result on a dvd, as i only put it on a cd).
i think you could also put it on a stick:
lh_congig -b usb-hdd --bootstrap --debian-installer live
dd if=debian.img of=$USBDRV
while debian.img must be replaced with the *.img result of lh_build.
(you got a nice live-cd or live-usb and a backup :-) )
or you could try chrooting into /, the partition its mounted on should be big enough
(i`d go for 3 times as big as the original). Well: you`d need a debian-live-cd with live-helper or a second installation for that.