set Control Visible?

I am trying a button. I need to show or hide it dynamicly. I tried

button.setControlVisible(false);
button.refresh();

and

button.setStyle("visibility", "hidden");
button.refresh();

They all don't work. What did I miss?

Thanks,

Shuld work, did you tested on a clean page?
Just try:
var obj = new AW.UI.Button;
obj.onControlClicked = function(){
this.setStyle("visibility", "hidden");
}  
document.write(obj );