From: DeskNow Knowledge Base
http://www.desknow.com/kb/

How do I map webfolders to a drive letter?
http://www.desknow.com/kb/idx/12/072/article/

The embedded WebDAV client in Windows Explorer does not let you map webfolders to a drive letter.

You can use a product like WebDrive ( http://www.webdrive.com , commercial) or Novell NetDrive ( http://support.novell.com/servlet/filedownload/uns/pub/ndrv41862.exe/ , free if you have an existing novell license), also available at http://www.loyola.edu/5555/netdrive/installingnetdrive/

... or just google for netdrive.