Hi Ignazio,

 > I'm trying to talk with some oFono developers to understand if my
> previous conclusion is correct or not, but I wasn't very lucky lately.
>

Essentially nothing registers an HandsfreeAudioAgent with oFono.  The 
only known implementation today exists as a plugin / module in PA. 
Patches have been submitted upstream and I believe they have mostly made 
it into the PA tree, but I lost track of the progress sometime in late 
November.

> As far as you know are there a way to solve that problem or if exist an
> anofficial version of PA that provide the support to blueZ5, oFono and
> so for bluetooth HFP?
>

You might try the latest upstream of PulseAudio.  But essentially this 
question should be asked on the PA mailing list.

Regards,
-Denis