The right assignment is under the "Radio VoIP" menu, that is under the general drop down menu (not the f18 drop down sub menu)... You have to check the That assignment brings only the radio menu as the name says.
_____________________________________________________________________________
BREAK BREAK
______________________________________________________________________________
I have, instead, two other issues:
The first is, when I plug in a new input device in game, it breaks the microphone input and cannot detect any sound from any mic. When you are the host it's very annoying.
The second problem is that I cannot hear anything from ONE SINGLE PLAYER, and that specific player cannot hear anything from me. I can hear all the other players, in any game, but the relationship between me and him seems to be disliked by DCS somehow.