How to access WebDAV shared folder on Mac OS X Server
Here is how it partially works.

The server's WebDAV interface is presented from a virtual directory "webdav". If your server is at 

https://theserver.domain.com 


then the beginning of your WebDAV access starts at:

https://theserver.domain.com/webdav/


This will typically be your "home folder" if the server is setup to offer users home folders.  

And while it does not represent your actual directory structure , all other shared volumes are tacked on to the end of that. So if you mark a folder as shared with "WebDAV" thusly:



then the access would be:

https://theserver.domain.com/webdav/swap/


Caveats:


URI is case sensitive
username aliases are not respected, you must use the "short name" for login, even from the Mac OS X Finder's friendly login dialog
Wiki storage access with WebDAV ... still not clear on the URI