1. Make sure you have Sopcast install. If you don’t, follow this post
2. Quit Sopcast if you are running
3. Open firefox, enter "about:config" (without the quote) in the Location bar, and click on the button in the warning page to continue
4. Right click anywhere in the config grid, select New->String
5. Enter the preference name: network.protocol-handler.app.sop and press OK
6. Enter string value: sopcast-player and press OK
7. Search for the network.protocol-handler.expose-all and set it to false
8. Restart Firefox and now try to open sop://link, there will be a dialog box ask you the program to open the link, navigate to /usr/bin/sopcast-player.
9. Now sopcast will be opened and played, enjoy!