Following a workaround mentioned on http://support.microsoft.com/kb/2512023 – “GetUserOofSettings”, “SetUserOofSettings” and “GetUserAvailability” operations do not support Exchange Impersonation on the Exchange Server 2010 SP1 schema
Seems like the EWS Managed API 1.1 download link does not work anymore, and it’s virtually impossible to get a hold of the files on the WEB, so I’ve uploaded the redistributable package here for anyone looking around for it.
Anyway – grab it here: Microsoft Exchange Web Services Managed API 1.1
Hope this helps.
Exchange Web Service Managed API 1.1, Download – Microsoft ( Non working download links) :