Please download and install the Linn KinskyDesktop from http://www.linn.co.uk/kinskydesktop
It can control your Marantz NA-7004
Please check whether your NAS has uPnP(DLNA) media server. If not I can bring my own
Please take note some of the NAS such as Synology cannot display the CD cover properly
Asset uPnP installed in a PC is the best that I found so far http://www.dbpoweramp.com/asset-upnp-dlna.htm