What do you mean with "switch back inside the VC", exactly ?
Are you using a 3rd party camera utility ? Could be the VC is not *really* the real VC view ? GSX will detect you switching to VC, and this is done precisely to control sounds, since some sounds are meant to be heard from the VC only ( but not from the outside ), and vice-versa so, if your VC view is not the standard one, the detection won't work.