I was having a hard time getting m3u (MP3 audio -- streamed) files open up in my external xmms audio player instead of the the default mplayerplug-in and found out that firefox by default hides the plugins without any extensions, as the mp3 playlist was being created dynamically with php and the mime-type fed via the header.
The work-around was to disable the default firefox config settings and change the option for streamed mp3 audio to be opened with xmms instead.
The steps are outlined below:
-
Type "about:config" on the address bar to get to firefox config settings.
Do a filter search for "hide_plugins" and double click on "browser.download.hide_plugins_without_extensions" to change the settings value to "false".
Open up "Edit > Preferences", go to the "Downloads" area and click on "View & Edit Actions".
It should now list all the "File Type". Do a search for audio and change the "MP3 audio (streamed)" to open up in the external xmms player.
See other posts on Firefox.