Sound volume control

programming flash
1

Dear people of Kirupa

I have a streaming sound loading into a flash project. I would like to control the volume with two simple buttons (but_volup, but_voldown). My streaming sound is called myMusic.
I got this code from a book but all it seams to do is mute and unmute the sound?

can anyone please help me?

but_volup.onRelease = function()
{
myMusic.setVolume(100);
};
but_voldown.onRelease = function()
{
myMusic.setVolume(20);
};