Thanks for the comments.
Question for sebi85. What did you do to get Wheezy on your LS-WVL (and others)?
I simply performed a dist upgrade from Squeeze to Wheezy
If I have some time, I will update these scripts to Debian Wheezy and fix the minor bugs:
a) The version of debootstrap in config.cfg is out of date and needed to be changed
I modified the comment in config.cfg to make clear that the version may have to be changed. That was the reason why I had stored the version in the config file.
b) prepare-rootfs.sh has a hard-coded name of the debootstrap .deb file that needed to be changed.
I should have noticed that by myself.
c) post-install.sh and config.cfg disappeared from /root when I rebooted a second time; I copied it again.
I think that was the desired behaviour to remove the files after the installation.