The-Mailman:
I'm an NAS newbie so bear with me here a bit.
I'm doing something similar and *might* have a tip for you, if you have a set-up similar to mine. By chance, did you move your files in iTunes using the iTunes consolidate tool? I did and successfully moved all my files to the NAS but could not see the playlists either. After doing this, I found out that the various iTunes files that tell iTunes where the files are were still on my C drive and that iTunes does not actually move those files when you do the consolidate thing. And that you have to move them yourself.
I am setting up a similar device (but not a Roku). Here is the advise I was given to move the iTunes files:
If you wish to store the library files permananetly on the NAS (and thus eliminate the need to copy the .xml file every time you make a new playlist), you should do the following:
1) Copy both the 'iTunes library.itl' and 'iTunes library.xml' files from the default directory to the share on the NAS
2) Start iTunes by holding down the Shift key and clicking the iTunes icon (make sure you keep holding down the Shift key).
3) You will be prompted to Choose a New iTunes library. Browse to and select the library file that you copied onto the NAS.
Your library, including playlists, will now be updated on the NAS, and will be shared with the device after a reindex.
That worked for me, only now I actually have the playlists showing twice and haven't sucessfully excised one of each. But I figure twice is better then none!
Anyway, this is probably only helpful if you're moving files from your C drive to your NAS using iTunes. Good luck!