title: Web API unsupported media type when uploading - charset not passed
body: <p>I'm developing a new web API and currently integrating (re-writing) the legacy API to work with the new one.  However I'm having issues with the Excel templates.  Every time I try do a POST I get a 415 unsupported media type error.  </p>
  
  <p>I have managed to make it work so I know my code is fine the problem is when I use the templates it sets the content type in the header to:</p>
  
  <pre><code>Content-Type: application/xml;
  </code></pre>
  
  <p>However, if I change the template to send:</p>
  
  <pre><code>Content-Type: application/xml; charset=utf-8
  </code></pre>
  
  <p>It works as I would expect.  The problem is I can't change the templates in production.  I have to make my code work with the templates as they are.</p>