Download the trial version of Interarchy from http://nolobe.com/interarchy/
Extract the app, and move to the Applications folder.
Open Interarchy, and you will see a window like this:
- In the protocol drop-down, select WebDAV
- In the server, type the IP or hostname you use to connect to your DNS-320
- You can either leave the port as default (80) or change it to 443
- Type in the username and password you have set for webdav access.
- In remote path type: /webdav/YOUR WEBDAV SHARE
- (Where YOUR WEBDAV SHARE is the name/path of the folder you have set as a web-dav share)
- Click List
This will connect you to your DNS-320 via webdav.