I have set up WebDAV over SSL on an IIS server running on Windows Server 2012. For the most part it works fine however I am having an aggravating issue with iCal clients running on Mac OS 10.6. Basically, I am intermittently unable to publish calendars, small calendars always seem to work, when a calendar reaches 1.5mb or so it starts to behave erratically, sometimes I am able to publish the calendar, other times when iCal states it is sending the calendar data, it will only make it about 1/3 of the way across the progress bar and then it fails with a message saying the server closed the connection.
If I connect to the WebDAV server using the Finder Go->Connect to Server menu on the same computer I am able to drag files into it with no problem, even ones that are much larger than the calendar files. When publishing calendars from the Calendar App on 10.7 or later I have so far not experienced the problem.
I think this is a long shot but if anyone has an idea why this might be happening I would really like to hear it.