You can access the Create Render Passes window by selecting mental ray as your renderer, then selecting the Passes tab, and clicking the New Pass button.
Select, from the list, the render passes that you want to create. You can multi-select render passes by shift-clicking or control-clicking.
All render pass presets that you have created are also available from this list.
Add a prefix or suffix to the render pass names of the passes that you are creating.
Select the Create Pass Set option to create a new pass set. All render passes that you created simultaneously with the render pass set are automatically associated with the set.
Click the Create and Close button to create the selected render passes and close the Create Render Passes window. Click the Create button to keep the Create Render Passes window open and create multiple versions of the selected passes.