When you enable the Synology Media Server on your NAS, there are 3 directories added to your file-system (video, music and photo) which will be used for the DLNA/UPnP media server to play the corresponding files.
I was searching for a solution to change / edit this. How to start
You have to enable ssh login. Then you can use putty to conect to your device
username root, password [your admin password]
navigate to the etc folder and create a file called rc.local .
syntax vi rc.local (vi editor is real painful editor so keep in mind this manual vi commands synology)
I added three entry’s (because I have also enabled nfs on my system for the popcorn media player)
mount –bind /volume1/[your path]/music /volume1/music
mount –bind /volume1/[your path]/photo /volume1/photo
mount –bind /volume1/[your path]/video /volume1/video
Save and exit the file :wq
while you have still your putty session open type reboot and hit Enter.
Thanks to http://dev.eek.be/