First off I am not sure if a SB16 is full duplex.
Take a gander at this: http://players.shoutclub.com/SHOUTcastFAQ.txt
Read "T10. Arrrrrrh!!!!!! I set all this stuff up but the listeners can not hear the damn music!!!!"
and try the stuff I posted there, if you still have problems come on back and we'll see what else we can do.
Did I just use the word gander? I need to get out of the Midwest quick before I get Hill-Billyfied.