The cable is faulty. I tried with another one from my dealer and it fully works!
I didn't know for the 2 cables. I have the 61120440796, not the 61120440812 and this could by the root cause. But, I think the dealer let me try the 61120440796 and it works. Also, both parts are made for 6FL, not COMBOX.
I will buy a new one and try again.
Edit: There is a guy on the french forum that use the same cable than me without any issue.