OK, lets see if UpdateMedia is populating the database then. The media grids where your media is shown are drawn from the database, not from a simple directory list. The database is populated by UpdateMedia. If you go to the admin site and choose File & Media menu, then Media File Sync, you can then navigate down through the directory structure as the database understands it in the left hand pane. Go to "audio", say, and you should see the Windows Share in there. Click into that and your NAS folders and files should be in there.
Depending on which version of LMCE you are using (Beta4 is best) you will have two tick boxes in the right pain to display attributes and files missing from disk - turn those on. If the admin tool can see a media file both on disk and in the database (ie they are in sync) it will have a big colourful tick next to it in the right pane. If it can only see it on disk but not in the database it will appear as a drive icon next to the file name. If it is only in the database and not on disk, these will be summarised at the bottom of the web page on the right pane noted as missing from disk.
For anything to appear in the media grids, they have to both have the big colourful tick and be on a share that is "online". You have confirmed the latter, so check the former now in the admin site.
BTW - what do you actually see in the media grid? Any media at all, not even local media on the Core? By default the media grids start in an attribute "sort" mode, so if your media doesn't have any attributes (either embedded as id3 tags, or as separate .id3 files with the same name) then the media grid will appear empty. You can check this quickly by choosing the "Sort" menu in the bottom left of the media grid, then choose Filename as the sort option. This will then let you navigate using a normal folder/file structure - your media doesn't have to have any attributes at all to appear in that mode....