Second of Three Parts . . .
This walks through how to actually set up our custom passes in Maya/Mental Ray using User Frame Buffers, Camera Output Passes and a shader buffer (I'm using Simple Passes: mymentalray.com/index.php?option=com_shaders&Itemid=108&Action=DisplayDetail&ObjectId=82). This basic workflow works in 2009/10, but there may be a few subtle differences . .