setMask ignored on dynamically loaded clip

programming flash
1

I am using movieClipLoader to load a swf into slideHolder


	slideLoader.loadClip(mediaPath + slideSWF,slideHolder);
	slideListener.onLoadInit = function(target:MovieClip)
	{
		slideHolder.setMask(zoomMask);
	};

It doesnt seem to be applying it :expressionless:

I know that is the right way to do it, but no luck! Whats wrong with it?