Using chroot to run partimage to backup hdinstalled knoppix?

I could use some hint on how to backup my knoppix partition without
booting on a cd.

I have my system on /hda1/ and I was wondering how I could be allowed
to umount it without having to boot on cdrom. I want to run partimage on it and it insists that it should not be mounted.

So how difficult is that?

Thx

well, it seems like the chroot command is not as powerfull as I
expected.
Even its easy to setup a chrrot inv with
the needed commands, its still not possible to umount the 'system' partition to
run partimage on it.

I guess its possible to boot into an image installed on another partition using a floppy
but thats not easier than using a cdrom.

So my questions is:

Is it possible to umount the system partition without booting
on other media (floppy, cdrom) ?

Like having a boot image on another partition and boot into that?

Thank you