Thought I would pass along this link to all who read browse this forum. I just recently released a free script called Null Swapper and a tutorial for it here:
It's a utility script to swap After Effects Null layers out for Light layers. Say when you want to use a 3D solved track with Plexus, you will need Point Lights for Plexus to work, and swapping tens to hundreds of Nulls for Lights is a crazy task to do by hand. That's why I made this script. Currently it is CS5.5 and CS6 only, but I am looking into a solution for previous AE versions.