When I tried box.net, I got a 404 initially. I have a folder called Documents, and the correct url turned out to be
https://www.box.net/dav//Documents. Anything without the 2 slashes results in a 404.
Unfortunately, I get the following error message:
Unable to synchronize database with server.
Unable to read document.
No root transactions found in “
https://www.box.net/dav//Documents/OmniFocus.ofocus/”.
When the drive is mounted through Finder, no files are present in the directory.