I totally forgot about this. But when watching the sublime movie ENNIO by Tornatore it came back to my mind, so after more than four years a solution should be given.
This young gentleman is Mr. John Heineman, trombone and cello player of the "Gruppo di Improvvisazione Nuova Consonanza". He's (or was?) a composer too.
Honestly I did not know exactly the solution. For a long time I kept thinking he was Walter Branchi. The doubt was cleared after the interviews of Mr. Branchi contained in ENNIO describing the Nuova Consonanza years of the Maestro.