Question: How to open a MP4 file from locale

I have a question about the internal video player, i always wonder if it was possible to play a locale (video or audio) file directly inside OWB using the internal player ..

So i go in Prefs/MIME Type and in MP4 section i set:

MIME Type: video
Extention: mp4
Action: internal viewer

Saved, then i drop a file into OWB ..
I was expected to see the video start playing inside OWB, however instead the browser will open an ASL requester that ask where to save the file !

So in alternative i tried instead to open an external video automatically by using an external video player (Emotion to say one)

So i've set:

MIME Type: video
Extention: mp4
Action: external viewer --> Viewer --> <Emotion binary path in my hd>

And more or less it works, but not in all conditions (details explain later eventually), atleast sometimes it only open the program but did not playing anything .. or just give me a message error saying that path need to be assigned

So the question is, in current state is it possible to open a locale file media file directly into OWB just by dropping into ?
Is that media thing working already as it was projected by Fab, or its just broken waiting for some more work ?