Embedded DLNA server is not only a disaster for music, but also for video.
Read my 3rd post here: http://community.wd.com/t5/My-Book-Live-Duo/Need-help-to-migrate-from-MBL-to-MBL-Duo/td-p/591341
As a conclusion, if you buy a MLBD, seriously consider adding some bucks for the twonky licence, otherwise do not expect a descent DLNA service