I believe that the ALSA users mailing list is a good place to look for answers to this, and to post such questions should you arrive at a loose end. Don't get me wrong, btw - I'm not saying that you shouldn't post it here by any means, it's just that it's more likely to be read by someone who knows the answer if you post it at ALSA.
http://www.alsa-project.org
Hope this helps!