Now that I managed to do the tricks I have another question:
How to associate application/x-mplayer2 with mplayer?
I added the necessary line in defaults.list, but it does not work. Maybe some other changes should be made.

Edit: I found this file /usr/share/applications/mimeinfo.cache and added in it 'application/x-mplayer2=hildon-dbus-switchboard.desktop'. As far as I can see this is a step in the right direction, but something more should be done as well...

Pipeline, please help. This is an important issue when watching live TV and other embedded content in Windows Media format.