Office 2013 Outlook Web app: The requested web method is unavailable to this caller or application.

 I am developing an Office 2013 outlook app. I am trying to delete a folder via the mailbox.makeEwsRequestAsync method. The response I receive has the following error: The requested web method is unavailable to this caller or application.

I used the following envelope.

<?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:t="http://schemas.microsoft.com/exchange/services/2006/types">  <soap:Header>     <t:RequestServerVersion Version="Exchange2013"/>  </soap:Header>  <soap:Body><DeleteFolder xmlns="http://schemas.microsoft.com/exchange/services/2006/messages"xmlns:t="http://schemas.microsoft.com/exchange/services/2006/types"DeleteType="HardDelete" >	
<FolderIds>		
<t:FolderId Id="AAMkADJiZDE5MzVhLTZmNWYtNDFmMy1hZGFiLWI3NGQ5YzdlZGU4ZAAuAAAAAADj8OeEjmcISqAvXbi9TwkWAQC/IIdDwcupSIXubBVrZICMAAAQ6V9TAAA=" />	
</FolderIds>
</DeleteFolder></soap:Body></soap:Envelope>

I found only a subset of EWS operations is supporting for outlook mail apps.
http://msdn.microsoft.com/en-us/library/fp160952.aspx
I just want to ask is there any other workaround to delete a folder from Office 2013 Outlook app.
Thanks.