ok, so i tried an nfs mount, but w/o the official documentation, i'm not sure i mounted it with the right options. plus, it's difficult to discover the uid of the user on the dns-321 w/o a shell. i assume there will be a gui enhancement in the future to solve this.
at this point, i'm really frustrated with the unit. it simply will not obey the file permissions i've set! i put a 50gig .dmg file on it last night, in the "Photos" directory. i watched, via command line, when the write started. the permissions at that point were 644, just as i would expect. however, after the file copy completed, the permissions are now, magically, 444 with no way to change them!