KDE image fails to build with Live Systems web autobuilder

Hi.

I tried to build KDE desktop based live image using the web autobuilder at: http://cgi.build.live-systems.org/cgi-bin/live-build

However I ran into several problems. Firstly, I needed Debian testing distribution, but it only had Wheezy and Sid. So, I went with Sid and set KDE desktop, amd64 where appropriate and enabled Debian installer.

Later the build failed, because some virtualbox packages were missing:

[2013-12-10 01:40:18] lb chroot_install-packages live
P: Begin installing packages (live pass)...
Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package virtualbox-guest-dkms
E: Unable to locate package virtualbox-guest-utils
E: Unable to locate package virtualbox-guest-x11

I noticed that they aren't in the main repository, but in contrib. I went back to the settings and tried to add contrib to Advanced bootstrap options: --archive-areas

However that field was read only. There was no way to explicitly exclude the faulty packages too. Did I miss something there, or it's a bug?

Regards,

Hillel Lubman.