I spent a day developing a set of DNG images in LR4 and then used Bridge to rename all the files. When I sync'ed the folder in LR the develop settings in the DNG files were not there, all zero'ed out. I thought the develop settings were stored inside a DNG file by default? Do I need to tell LR to do that? I don't see where that setting might be.
Only when you Save the metadata to the DNG in Lightroom...(unless you have the save xmp automatically turned on). Otherwise the settings are only stored in the LR catalog.
In Lr, I think the default is to store develop settings in catalog only.
To store in DNG files, hit Ctrl/Cmd-S, or enable auto-save xmp in prefs.
Edit Menu -> Preferences -> General Tab -> Catalog Settings -> 'Automatically write changes into XMP'.
I prefer the manual method for a variety of reasons, but others prefer the automatic method (mostly so they don't forget I guess).