In the shoutcast source box with the port, input, output and everything, under input there there is a button that says press to talk. that will lower the music so you can talk, after you are done lift your finger of the button and the music will go back to normal.
I'd like to try again in a few hours. If no one important is using it around 3pm EST, I'd like to. If someone already has that time, then I'll wait till it is available.