make your new render layer

assign all the objects to it (or just select the objects before hand and make a render layer with the selected objects)

then go into your render settings, switch to mental ray

in the passes tab click one of the buttons on the right of the scene passes white box thing
then click on the down arrow beneath it with the +

then hit batch render and you get your occlusion and master beauty pass

that's how it's meant to work i think...