I have updated everything with 'apt-get' and have only unstable Apt repositories in my sources.list - but still there's some 'knoppix stuff' left:

root@abc:~# dpkg -l | grep -i knopp
ii ash-knoppix 0.2-4 A smaller version of the Bourne shell enhanc
ii captive-ntfs-k 0.5-1 knoppix menu item for calling the captive-nt
ii configure-xawt 0.1-6 pre-configures xawtv for use with knoppix
ii ddcxinfo-knopp 0.6-5 Monitor/Graphics card DDC hardware detection
ii etcskel-knoppi 0.6-26 Skeleton files for all user
ii hotplug-knoppi 0.5-7 hotplug handler for KNOPPIX
ii hwdata-knoppix 0.101-3 hardware identification / configuration data
ii kdelock-knoppi 0.5-1 Replaces the kdesktop_lock with non-locking
ii knoppix-bookma 0.5-2 Bookmark file templates for KNOPPIX
ii knoppix-custom 0.07-2 change boot options and files of a KNOPPIX i
ii knoppix-graphi 3.4-2 The background wallpaper and ksplash graphic
ii knoppix-menu 0.5-2 Menu structure and icons for the KDE/GNOME K
ii knoppix-remoun 0.5-2 Minimalistic script for r/w remount of parti
ii knoppix-sounds 0.5-1 2 of the Space Sounds taken from the Mandrak
ii knoppix-termin 0.5-18 Starts all services necessary to boot KNOPPI
ii knx-alsa 0.1-7 brings alsa to knoppix
ii knx-installer 0.3-3 installs knoppix to hd
ii kudzu-knoppix 1.1.3-3 The Red Hat Linux hardware probing tool.
ii kudzu-knoppix- 1.1.3-3 Hardware detecting library
ii kudzu-knoppix- 1.1.3-3 Hardware detecting library
ii linux-wlan-ng- knoppix+0.2.0- drivers for wireless prism2 cards
ii mkpersistentho 0.5-5 Shell GUI for generation of a KNOPPIX persis
ii rebuildfstab-k 0.5-6 fstab-rebuilder for KNOPPIX
ii restartx-knopp 0.5-2 Shell GUI for restarting KNOPPIX desktop
ii sambastart-kno 0.1-3 adds an sambastartup script to knoppix
ii saveconfig-kno 0.5-12 Shell GUI for generation of a KNOPPIX config
ii scanpartitions 0.5-5 fstab-helper for KNOPPIX
ii sshstart-knopp 0.5-2 Starts SSH and sets a password for the knopp
ii sudoers-knoppi 0.5-1 /etc/sudoers for the knoppix user
ii syslinux-knopp 2.04-1 Bootloader for Linux/i386 using MS-DOS flopp
ii sysvinit 2.84-176 System-V like init with KNOPPIX scripts.
hc sysvinit-knopp 2.84-1 System-V like init with KNOPPIX scripts.
ii user-profile-k 0.6-26 Skeleton files for the KNOPPIX default user
ii usleep-knoppix 0.5-1 sleeps for a number of microseconds, see man
ii xsession-inits 0.5-11 Starts X-Window system from INIT on KNOPPIX
ii xsession-knopp 0.5-48 Automatic Xsession startup script for KNOPPI
root@abc:~#

Is it possible to replace these with genuine Debian packages? How to do that?

I'm satisfied with my Knoppix but some of my Debian friends don't think that Knoppix hd-install would ever be compared with pure Debian install. What do you think?