Open up Photoshop 7, and open the antialiased render and the mask. Press ctrl-a with the mask showing and then ctrl-c. Go to the render of the scene and press ctrl-v. Select the magic wand tool. Click on one of the white areas of the mask, then hold shift and click on the other white area. In the kayers pallate click the eye right beside the mask layer to toggle vision. You now have a selection of the pillows. I don't know exactly what you want to do with them though, so it's up to you what you do now that you have the selection.