Looking closely, FreeNAS included fuppes 0.660 starting in 7.1 (http://freenas.org/changelog) which is when users starting reporting that fuppes and DLNA started becoming an issue.
Looking at fuppes SVN log (http://fuppes.ulrich-voelkel.de/download/) we can see "revision: 664 - date: 19. Mar 2010 - 21:57:14 - fixed dnla config setting: dlna tag now shows up in description.xml" and in the change log "https://fuppes.svn.sourceforge.net/svnroot/fuppes/trunk/ChangeLog) we see "* dlna fixes" for an untitled SVN.
So the question is how do we suck the changes upto Fuppes SVN 680 into a new build of FreeNAS 7x? Given FreeNAS doesn't list releases prior to 7.2 (with the exception of a source build) it's effectively useless UPnP service for DLNA at the moment.