Peter Palfrader suggested that I used 'apt-get install -t experimental apt-listchanges tasksel aptitude', and this worked just fine. I had used 'apt-get install apt/experimental' and tried to use a similar line for the other packages (apt-get install aptitude/experimental' etc). the latter did not work, while Peters suggestion worked just fine.
So, the only real issue left in this bug report is upgrading the GPG key included in the package. :) -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]