Re the kmix problem, I too had the same problem when remastering fior the first time. I don't even have sound on my test box, but I remastered and it went away. I have remastered a few times since and it did not show up again. I suspect I clicked on something in the kde control centre that made it happen the first time.

re the background image, the following proved useful for me in conjunction with the great HOWTO by Underscore.

It's from http://www.knoppix-std.org/docs/customize.html the site also has some info on how to insert default cheat codes etc into syslinux.cfg I also read somewhere else that you may need to pad out the syslinux.cfg file if u edit it, so just add or subtract the hashes at the end of the file to match the number of characters that you added or subtracted from the original file.

Edit your preferences: The preferences for the knoppix user account are set under /etc/skel/. For instance, the KDE K-Menu can be found under: /etc/skel/.kde/share/applnk/. This gets copied to the /home/knoppix directory on boot. Other preferences you might want to configure:

/etc/init.d/knoppix-autoconfig : knoppix boot options, like which windows manager to load
/etc/skel/.mozilla/knoppix/ujixazk6.slt/bookmarks.html : Mozilla bookmarks
/etc/skel/.kde/share/config/kickerrc : KDE Kicker panel
/usr/local/lib/knoppix.jpg and /cdrom/KNOPPIX/background.jpg : background image : 1024x768
/usr/share/apps/ksplash/pics/splash_top.png : KDE loading splash screen : 400x244

You can also create users and set passwords while in the chroot'ed environment.

Now my current problem is getting my kmenu modifications to stick after compressing and making the iso. My remaster remains intact but the new iso puts back all the kmenu items that I removed, back to default kmenu. Kmenu items for new software additions appear to remain however? Anyone found a solution to that?

have fun!