I'm not sure if this is what you are referring to, but I used to be able to click on a mp3 file and it would automatically start playing while downloading. Now it prompts me to download it before I can play it. There is a setting in HFS under Other Options and then Open directly in browser... In there you can add ;*.mp3 at the end and allow mp3's to automatically start playing once clicked. Again...not sure if this is what you were looking for.