Masking Problem

This problem sounds easy to solve so lets hope it stays that way.

I have a movieclip with a layer above it that is set as a mask.

I want it so that the content on the mask layer is VISIBLE when it isn’t over the layer beneath it.

So for example if I had a white background. I make a small black box that is in the middle of the stage and then make another layer above it that is a mask. I make a small red circle.

I want it so that the small red circle is visible as a small red circle when it isnt over the black box.

Cheers

williby27