OpenBrick mic input problem

Hello OpenBrick List:

         Has anyone successfully used the mic input on the OB?  I am 
using Darkice to stream the line or mic input from /dev/dsp to an 
Icecast2 server.  The line input works fine, but when I switch the mixer 
to use the mic input instead, I get only silence.  Switching back to 
line plays the line source.  I configured the soundcard using "modprobe 
sb", and I see all of the devices.  I can look at all of the associated 
gains/settings using aumix, and everything looks fine, I can see the mic 
input switch from Play to Record, but still no sound from /dev/dsp.  I 
can't think of what else I might be missing here.  If anyone has used 
the mic input, any simple ideas as to how to test it would be really 
helpful. 

Thanks,
            Scott Roberts