[Zope] Packless sessions with DBTab

I noticed that ExternalMount had been deprecated and replaced by DBTab. I'm in the process of attempting to set up some sort of nonundoing storage for 2.6's sessioning mechanics for use with a ZEO installation. Because all of the documentation is for previous versions of all the different pieces of the puzzle, I've succeeded in totally confusing myself. Is there a new procedure for setting up packless storage for use on Zeo clients? Which Berkeley DB are folks using with 2.6? Should I perhaps just take a long nap first? Thanks! Chris