That's because we have signature checks on our server. In ARMA I, we had VOP sound on as one of the allowed sigs, but because it changes things in game, we can't use it as in ARMA I, that's how scripts got broken a lot of the time on our servers, people having game changing mods.
I actually came here to ask if you guys could make a version that just changes sounds and nothing else (by nothing else, I mean things like the turret not turning on the vehicle).
If you can, that'd be greatly appreciated. :)