title: Amazon (AWS) - The request must contain the parameter Signature
body: <p>I'm struggling with the final part of getting my first bit of code working with the AWS - I have got this far, I attached the web reference in VS and this have this</p>
  
  <pre><code>amazon.AWSECommerceService service = new amazon.AWSECommerceService();
  
  // prepare an ItemSearch request
  amazon.ItemSearchRequest request = new amazon.ItemSearchRequest();
  request.SearchIndex = "DVD";
  request.Title = "scream";
  request.ResponseGroup = new string[] { "Small" };
  
  amazon.ItemSearch itemSearch = new amazon.ItemSearch();
  itemSearch.AssociateTag = "";
  itemSearch.Request = new ItemSearchRequest[] { request };
  itemSearch.AWSAccessKeyId = ConfigurationManager.AppSettings["AwsAccessKeyId"];
  
  itemSearch.Request = new ItemSearchRequest[] { request };
  ItemSearchResponse response = service.ItemSearch(itemSearch);
  
  // write out the results
  foreach (var item in response.Items[0].Item)
  {
      Response.Write(item.ItemAttributes.Title + "&lt;br&gt;");
  }
  </code></pre>
  
  <p>I get the error</p>
  
  <pre><code>The request must contain the parameter Signature.
  </code></pre>
  
  <p>I know you have to 'sign' requests now, but can't figure out 'where' I would do this or how?  any help greatly appreciated?</p>