Traditionally there is only one 'source' password for live streaming to your Shoutcast or Icecast server. This password is managed under "Settings" in Centovacast.
If your account is set up on a Centova server, then you can configure additional DJ accounts with specific permissions for controlling the stream. However for the DJs to perform live streams, AutoDJ must be enabled. This is because it is the AutoDJ service which opens up the special ports (your streaming port + 2 and +4) that allow them access to perform a live stream using their own login credentials.
When you enable AutoDJ (under Settings > AutoDJ tab), you will be required to set up a general rotation playlist before you can start your stream again. When your DJs disconnect, the media you upload and add to your general rotation will automatically kick in until someone else begins a live stream. You can configure your DJ accounts with access to Centova so that they may log in and stop the AutoDJ from playing once their stream is done if you wish.