flex 4: skinning toggle button with images

I'm trying to skin a button with images.

i added the following css code:

.muteVolumeButton {
    upSkin: Embed(source='images/sound-mute.gif');
    overSkin:Embed(source='images/sound-hover.gif');
    downSkin: Embed(source='images/sound-on.gif');
   开发者_开发知识库 disabledSkin: Embed(source='images/sound-mute.gif');

}

when the button is clicked i can't see any images. any ideas ?

Which version you are using? In Flex 4 you have to use up, over and down. No need to specify upSkin, overSkin etc...for a gumbo package components.