title: API Gateway Proxy Integration - Corrupted file
body: <p>I created an API Gateway Proxy Integration so I can access a HTTP API on an HTTPS site. This HTTP API return a .xml file that is being returned by the API Gateway. But this file is getting corrupted by the Gateway, don't know exactly why. I saw some similar situations and find out that I should add this on my HTTP Header (Integration Request):</p>
  
  <pre><code>Name      Mapped from
  Accept    method.request.header.Accept
  </code></pre>
  
  <p>With that, when I send <code>Accept:"application/vnd.ms-excel</code> on my request, the file is returned OK.</p>
  
  <p>Although, my problem is that I can't change the request. Is there a way that I can add this header on API Gateway without using lambda integration?</p>
  
  <p>Thanks in advance.</p>