I just tested the following in a real install of Precise:
Set the active-card property of xfce4-mixer to "PlaybackBuiltinAudioAnalogStereoPulseAudioMixer" (not to what was suggested by #3).
Then the mute/unmute multimedia buttons work. Volume-changes performed by the multimedia-buttons are still reflected by xfce4-mixer, indicator-sound and xfce4-notifyd.
Volume-changes in xfce4-mixer (by clicking and dragging the sliders) is also reflected in indicator-sound and xfce4-notifyd.
So far I couldn't find any regressions in this setting.
I just tested the following in a real install of Precise: nAudioAnalogSte reoPulseAudioMi xer" (not to what was suggested by #3).
Set the active-card property of xfce4-mixer to "PlaybackBuilti
Then the mute/unmute multimedia buttons work. Volume-changes performed by the multimedia-buttons are still reflected by xfce4-mixer, indicator-sound and xfce4-notifyd.
Volume-changes in xfce4-mixer (by clicking and dragging the sliders) is also reflected in indicator-sound and xfce4-notifyd.
So far I couldn't find any regressions in this setting.