You actually have your OS on the DNS-323? I never went that far I just all my personal data on it.
You can not index because that requires the server to index in a form that Windows 7 will accept and as far as I know there is no such application that would do that on the DNS-323, but that doesn't mean you can't get your Documents and such folders on the DNS-323, you just have to fool Windows 7 as to where they are.
And note that if you actually have everything on the DNS-323 then "linking" might or might work for you, because in fact you would be doing a link on the DNS-323 (Linux) not on a Windows drive. And of course to do linking on the DNS-323 itself you would have to have shell access and such.
So anyway here is my setup.
C:\Users\Chris is where my user account is and is a Windows drive.
And now say I want C:\Users\Chris\Documents to be at:
\\DLink-NAS\Users\Chris\Documents.
First all I log into a different account and copy all the files from C:\Users\Chris\Documents to \\DLink-NAS\Users\Chris\Documents.
next just I right click on the "Command Prompt" and select to run as administrator.
Now go to C:\Users\Chris and do:
move Documents Documents.hold
Next:
mklink /D Documents \\DLink-NAS\Users\Chris\Documents
This creates a link from C:\Users\Chris\Documents to \\DLink-NAS\Users\Chris\Documents and basically from that point on programs that refer to C:\Users\Chris\Documents won't even know they are in fact talking to \\DLink-NAS\Users\Chris\Documents.
Repeat for all directories you want to move.
After you are sure of things you can get rid of the *.hold directories.
One other note to remove a directory link use: rd