After almost seven years, I'm sorry to inform you that this plugin is now deprecated and it won't be updated anymore.
The main reason behind this decision is that many other plugins do the same thing well, or better, or way more better than this one.
This plugin started in 2007 and WordPress evolved a lot in that timeframe: today the same tasks can be accomplished in a cleaner way with Pods Framework or Posts To Posts. Their user communities are way bigger than this one too, this mean better documentation, solid code, and more people willing to help on the support forums.
It has been a pleasure and a privilege to work with / learn from the community on this opensource project. Thank you all.