This is another feature request, but this time I'm not sure if there might be a way to get around it in current builds of SAM Broadcaster.
Icecast supports listener authentication via HTTP Basic Authentication and I know a bunch of stations who use such password protected streams for sharing streams with other stations or sublicensing some of their shows for live rebroadcasting.
Would be great if SAM could access HTTP Basic Auth protected streams and other HTTP resources.
This would also be great for PAL when you trigger the WebToFile stuff and make it download password protected files for later playback.
You usually can circumvent the basic auth dialogues in Desktop browsers by supplying username and password in front of the URL, separated by the @ symbol.
-> Login with "user" and "password" => http://user:firstname.lastname@example.org
Apparently that method does not work with SAM Broadcaster. (AFAIK the browsers just translate that special URL into sending the proper HTTP Basic Auth headers with their GET request)