Transmission BitTorrent setup for watch-dir - is this possible and how?

[stagger321]

Lo there.

So I have just taken delivery of a Linkstation LS220D
After the firmware upgrade I have turned on the BitTorrent client and am pleased to see its the latest version of Transmission.
On a prior machine I edited the settings.json file to add enties for a watch-dir.
That way you can drag'n'drop any downloaded set of torrent files into a windows network directory pointing at the LS220 transmission->watch-dir directory. A few seconds later Transmission picks up the torrents and processes them.
It all makes life a tad easier.
I see that the settings file is visible in the windows network folder but cannot be opened or edited.
Is this possible?, Or if not, is there a watch-dir set in that settings.json file and which transmission directory does it point at?

Cheers

Stagger