debconf-apt-progress -- apt-get -q --no-install-recommends -y install mythbuntu-backend-master^

seed:

laga@moar:~/dev/mythbuntu/seeds/mythbuntu.hardy$ cat backend-master
Task-Section: user
Task-Description: Mythbuntu master backend
Task-Extended-Description: This task installs a MythTV master backend and a mysql server
Task-Extended-Description: server system.
Task-Per-Derivative: 1
Task-Key: mythtv-backend-master

 * mythtv-backend-master
 * mythbuntu-desktop