You can have as many channels as are available on a single transponder and view any/all of them.
On my system I have set in the Media Server:
Server Mode: Shoutcast
Format: Stream Type: Transport stream/All streams
Click on Select channels and you will get a list of the channels on the transponder you are tuned to. Select the ones you want. Unfortunately (a bug to be fixed!!!!) the selection will not be preserved when you stop and re-start ProgDVB so you will have to go and select them each time you re-start ProgDVB. These are the <channel names> in the step below.
Network: Leave as is. Change the port if you want (I have mine set to 8080)
Click Apply and ok.
Re-open the dialog (Service/Prog Media Server from the menu) and you should see the URL has changed.
On my server I then set up VLC to transcode the output to h.264 and stream it onto individual ports, one port per channel. Without this it doesn't seem possible to see the channel on a remote machine. You can set up the stream from VLC as either Unicast or Multicast.
To view the stream on the server open VLC and select media/open network stream. Put in
http://127.0.0.1:8080/<channel name>
Click play and you should see the correct channel.
On your clients (I'm using VLC) open a stream with address http://<server IP>:<port set for VLC streaming> and you should see your channel.