Pulse Audio Sound Levels

[Lanoxx]

Hi,

I have a sound system from Teufel (Concept C 200) which has a built in 
USB sound card and an analogue aux input. When I connect the USB cable 
to my computer and the aux cable to my radio, then the sound of the 
radio does not play. When I unplug the USB cable the sound from the 
radio starts playing immediately. I have found out from the hardware 
manual that the sound card is able to control the aux output and mute it 
or control the volume. On windows it is possible to simultaneously 
enable both usb and aux inputs (see [1]). I have not found any way to do 
the same in Ubuntu so far and I would like to know if this is a bug (or 
missing feature) in which case I would report it on launchpad, or if I 
simply haven't found the right option.

I have already tried to use alsamixer and pavucontrol. In alsamixer i 
can see that the usb sound card has separate "speaker" and "line" 
devices, but changing the volume does not affect the output. In 
pavucontrol there is simply no way to see the difference between 
"speaker" and "line" as there is only a single volume control for the 
usb sound card.

Regards
Sebastian

[1] imageshack.us/photo/my-images/716/soundlevels.png