Manual selection on the 320?

[dartagnan]

if you "force" radio (manual selection)for the VOR, can the plane still update his position from VOR stations?

[OPEN DES]

Yes.

Go to DATA
POSITION MONITOR
SEL NAVAIDS

and you will see which VOR and DMEs are used for position updating. Not necessarily the ones you will see on your ND (manual or autotuned).