There has to be some way to configure pulseaudio before it's installed; most users won't put "oh, I just installed rhythmbox and now my sound doesn't work" and "I need to update my chroot to refresh the audio target because pulseaudio was installed" together.
 
In the worst case, we could add an apt.conf that uses a `Dpkg::Post-Invoke {"command";};` to check if the paconfig now exists, updates it, and deletes itself...but that's really ugly.