I am not, nor have I ever been a fan of the Real Player however, since I found this this evening I felt compelled to post it's availability for those whom you just can't pry Real player out of their cold dead hands.
With this codec installed on your system and Real Player associated for .pls files, any ogg or mp3 stream from Streamer will play using the Real Player as an external player.
THe better solution? Tell Real Player not to play anything but Real files, and go get a copy of the latest WInamp. It will play ANYTHING that is on Streamer that can't play within Streamer itself.