why not copy it straight to the hdd?
Knoppix will ofcource mount your hdd read-only by default.
thre are ways arount that.

As root (sudo su - as it is only one coand), run
Code:
sudo su - remountrw /dev/sdXY
where X is your hdd's letter (a, b..) and Y is the device number.

Now you should first rename the old xf86config-4 to say old-xf86config-4,
next copy /etc/X11/xf86config-4 to the /etc/X11 directory on that recently reounted drive.
that should be it.
reboot and enjoy