I do mine manually. Hope this is not too basic and helps.
I go to shoutcast website, click on "tune in" to test a station to see if I like it. If I do, I add it to a Winamp playlist (or create one and add it, if I want a new category of playlists). I get the ip string by looking at Winamp's Media Library screen for the playlist. I then can just manually add the new string to a playlist using Notepad. See example below. Is pretty simple. Just make sure the number of entries at the end is accurate and increment the fileX, TitleX, LengthX as you add more entries. Good Luck. (whoops - I can't leave html. I will try to csubstitute something and see if it clears. Sorry I couldn't get it to clear. Try creating and opening a Winamp playlist in Notepad. You should be able to figure it out)
It's even easier than you think. (I had the same problem as you. I wanted to listen to Soma.FM channels and not use Shoutcast). So, don't use the Shoutcast application.
The Galleon Music application will recognize and play *.m3u and *.pls files - which include streams. Create (define) a new Music application. Change the directory to where you keep your music files (I've one just for my *.m3u and *.pls files - which has all my preferred channels.) and Apply.
On your TiVo, head over to Photos & more, select Music and now you should see all of your m3u & pls files. Move into to selection, and you'll see every stream listed from the file.
Now, what's in these files? Simply a list of stream URLs. (Be sure to read the Galleon docs about one of the Port caveats.) There is some formatting differences between the files. I had some boss examples from my Soma.FM's Secret Agent files but the BB was nagging about the URLs -- pos. Check out "soma.fm" for their official PLS files.