[LAU] screencast using jack

[Federico Bruni]

I'm trying to figure out how to make a screencast using jack.
I have a microphone connected to a firewire soundcard.

I've already excluded recordmydesktop, at least for the audio track, 
because of this bug:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=649824

"recordmydesktop: Specifying --use-jack makes recordmydesktop exit with 
a bad screen geometry"

recordmydesktop works fine if run without --use-jack. I may use it for 
video only. What about audio?
I'm trying jack_capture, which seems nice but I can't make it work: the 
.wav file generated is mute.

Can you help me?

Thanks
-- 
Federico