Sorry to Lazarus this old post but after scouring the forums it seems this is the closest thing to what I am trying to find out (but not quite). So rather than create a new post...

When I first got my DS411j I moved my entire iTunes media library (with the iTunes managed folder structure including music, movies, TV shows, apps & books etc) onto the NAS default "Music" folder from my MacBook local HDD.
I have since added some movies into the NAS default "Video" folder.
I play music/movies etc on my MacBook via iTunes (sourcing from the NAS default music folder) and watch my other movies with XBMC (sourced from the NAS default video folder). All has run smoothly.
My first question was whether there was any performance advantage to using the default folders for storing and viewing the media in this way?
So moving on.
The separation of my iTunes media and my other media is bugging me and I want to get it all into the same consolidated iTunes folder structure.
So I tried creating another shared folder on the DS411j called "Media_Share" and I moved the iTunes media library into this folder. I was hoping I could just move all my media (the other movies etc from the default video folder) into this folder and use it all in the same way that I had been, just with it all in the consolidated iTunes folder structure. When I began playing music on my MacBook via iTunes (like I had done before) it seemed to me that my LAN access was slowing down as iTunes was really hammering it accessing the NAS.
So, to my other questions;
Is the performance hit just a figment of my imagination (theoretically speaking of course as I know you'd need some network traffic data to confirm it... which I don't have)?
Is it possible to have the consolidated iTunes folder structure I am looking for without a major hit to the performance?
Is my "Media_Share" folder the right way to do this or is there a better way?
I spose what I'd really like is to be able to have iTunes be the media manager and music player while XBMC sources it's movies from the iTunes media library.
Thanks for any help you can give me.