I am using Flash CS5 to make a slideshow of images: 4-5 images that fade, transitioning into the other. I would like to make it so that the corners of the entire slideshow are rounded and transparent. I want to do this on the slideshow level as opposed to just editing the images themselves so that this slideshow can serve as a template where any images can be dropped into it.
The person that worked at this position before me made some templates with rounded corners, but I cannot figure out how to duplicate how he did it. As far as I can tell, he merely made a layer on top of all of the other layers and filled in the area he wanted to be transparent with white. When I do the same it doesn't work, so there must be a step I am missing.