From https://developers.google.com/cast/docs/media

Audio decoding

• HE-AAC
• LC-AAC
• CELT/Opus
• MP3
• Vorbis

So, it won't support Real Audio or WMA (or FLAC strangely enough)

Though I've yet to find a station that doesn't use at least one of the supported formats.

Gah! Was hoping you'd already have this up and sorted! Still, I would probably switch over to you if you get Chromecast support sorted even if you don't have as many (BBC are missing for a start)

Please somebody get this done, I'd absolutely love internet radio on my Chromecast without having to use my laptop!