You won't be able to do that. The favorite channel of the Slingplayer is depenant on the Zap2it electronic program guide. So, you will only be able to add the channels from it to the mobile favorite list.
I can only think of a couple ways around it. If your set-top box has a "favorite" feature of its own you could program it to save your "extra" channels. Otherwise, if you had a Slingbox with a built-in TV tuner (Tuner, Pro, and Pro-HD) then you could just scan the ANT IN channels for your CCTV extra channels.
thanks for your answer so that you know i have sling HD and the signals being embeded in my cable are digital like 12.3 i can dial them up directly just wanted to add them to favorites because we use a few of the here for security cams info networks and sky cams. hope they add this feature in future release.