The new speaker volume applet (don't know the correct name) has no way to switch the audio-profiles for the configured soundcard. I use a SPDIF-connection to my amp with a SB Audigy card. I had to install pavucontrol manually and switch the profile to 'Output Digital Stereo (IEC958) + Input Analog Stereo' to hear something. The profile selection should be added to the audio settings for the new speaker volume applet on its output-tab in respect to the selected output-device.
Already known upstream: http://bugzilla.gnome.org/show_bug.cgi?id=572217