how to make a custom asound.conf part

[OlafM]

I like to add system sound. As I do not want to interrupt the MPD, I like to use dmix and add an channel which plays the system sounds. I tried to figure out, how the asound.Conf file is built up. However, these have a heading "Managed by Moode", which I do not like to modify.  How can I do this in a proper way? And I do understand, that from sound quality the dmix is not appreciated. But for this particular project it is valuable. Thanks for your guidenance.