Add music from itunes server on network (NAS)

I'm trying to add music from my NAS to my iphone 5 using Itunes 11. It sees the NAS as an itunes server, I can browse and play music without issues, but copying is grey'd out. I have 12,000 tracks on my NAS for same keeping and playing in various ways but itunes wont let me use it. Tearing my hair out here,

thanks