I know how to play video files over HDS, but how to play mp3 files?

To play video files we can use url like this:

http://localhost/hds-vod/sample.mp4.f4m

http://localhost/hls-vod/sample.mp4.m3u8

and this works!

but i can not play mp3 files in same way, if i use url like this:

http://localhost/hds-vod/sample.mp3.f4m

http://localhost/hls-vod/sample.mp3.m3u8

'sample.mp4' and 'sample.mp3' files are under same location: C:\Program Files\Adobe\Flash Media Server 4.5\webroot\vod

What i have to do to play mp3 files over HDS or HLS?