I think what Captain Bravo means is to make an
addon, which adds new ingame sounds, available
like the ones, already in the game.
Like BAS did on their Tohnal island, where it gives
you new sounds/music/FX options in the trigger
or waypoint's effect menu's.
I am not familar with addon making, therefore i can only
suggest you to have a look onto addon-making or let your
thread move over to addon making.
I can only assume, but i believe it has to be done similar
to adding sound to your missions (description.ext file),
and to include your sound.wss or sound.ogg files.
Maybe a config.cpp file too, and then pbo'ing all together.
Then you would put it into the addons folder, and you should
be able to access them.
As i already said, if it's that what you want, head over to
addon-making.
~S~ CD