Moodle reports "No files available" when connecting to a WebDAV server running IIS 7.5 on Server 2008 R2. iOS devices and Windows computers can connect and use the WebDAV server as expected. Please contact me if you require a test account to use for debugging.

Contacted Frédéric Massart who said:

"is definitely a bug from Moodle... The problem might be caused by the IIS which would behave a bit differently than Apache and expect a different XML value sent through (...might need to have a look at wevdavlib.php webdav_client::ls())."

Thanks