I have a BD-C5500 which can see my DNS 323, the file structure is a little different when viewing via the BD-c5500, need to go into Video/folders and then i can see the DNS share structure.
I had trouble setting up the network setting first off, go to test network in the menu and make sure it's all good. Mine eventually worked with a bit of test / restart BD. then i just "changed device" via the RED remote button and it found the dns fine.
Hope this helps