recordmydesktop can record audio only from one source at a time

[luquino]

I'm using Ubuntu 9.10 AMD64 with Pulseaudio 0.9.19. When I try to record a clip of my desktop using recordmydesktop I can record audio only from one source at a time (i.e.: the usb microphone, the internal audio). During the recording I have to switch manually the input source from the pavucontrol dialogue. I red somewhere that using Jack I should be able to mix the two input channel in the same sink, but I wish not to install Jack on my pc. Pulseaudio can't mix the channels?