title: eBay FindingAPI - findItemsByProduct returns 'Invalid product ID value' error for EBAY-US site
body: <p>I'm trying to integrate eBay API in my project.
  I use ZendFramework and there is library for eBay FindingAPI, but it doesn't work for method <code>findItemsByProduct</code>.</p>
  
  <p>For understanding problem I wrote my small class:</p>
  
  <pre><code>&lt;?php
  class MyProject_Model_Ebay 
  {
      const FINDING_API_URL = 'http://svcs.ebay.com/services/search/FindingService/v1?';
  
      private $appId;
  
      public function __construct($appId)
      {
          $this-&gt;appId = $appId;
      }
  
      public function findByProduct($id, $type = 'UPC')
      {
          $params = array(
              'productId.@type' =&gt; $type,
              'productId' =&gt; $id,
          );
  
          return $this-&gt;doApiRequest('findItemsByProduct', $params);
      }
  
      public function findByKeywords($keywords)
      {
          $params = array(
              'keywords' =&gt; $keywords,
          );
  
          return $this-&gt;doApiRequest('findItemsByKeywords', $params);
      }
  
  
      private function doApiRequest($operationName, $payload)
      {
  
          $global = array(
              'OPERATION-NAME' =&gt; $operationName,
              'SECURITY-APPNAME' =&gt; $this-&gt;appId,
              'GLOBAL-ID' =&gt; 'EBAY-US',
              'SERVICE-VERSION' =&gt; '1.0.0',
              'MESSAGE-ENCODING' =&gt; 'UTF-8',
              'RESPONSE-DATA-FORMAT' =&gt; 'JSON',
          );
  
          $ret = file_get_contents(
              self::FINDING_API_URL . http_build_query($global) . '&amp;REST-PAYLOAD&amp;' . http_build_query($payload)
          );
  
          return $ret;
      }
  
  }
  </code></pre>
  
  <p>Method <code>findItemsByKeywords</code> works OK, but <code>findItemsByProduct</code> still returns error </p>
  
  <blockquote>
    <p>Invalid product ID value.</p>
  </blockquote>
  
  <p>I tried different variants of passing value, but it doesn't work :( Current version of passing value I saw here: <a href="https://stackoverflow.com/questions/4110440/how-to-use-python-xml-etree-elementtree-to-parse-ebay-api-response">how to use python xml.etree.ElementTree to parse eBay API response?</a></p>
  
  <p>Usage:</p>
  
  <pre><code>&lt;?php
  $eBay = new MyProject_Model_Ebay(
      'My-app-id'
  );
  
  $eBay-&gt;findByProduct('4719331316129');
  </code></pre>
  
  <p>Response:</p>
  
  <pre><code>{"findItemsByProductResponse":[{"ack":["Failure"],"errorMessage":[{"error":[{"errorId":["41"],"domain":["Marketplace"],"severity":["Error"],"category":["Request"],"message":["Invalid product ID value."],"subdomain":["Search"],"parameter":["4719331316129"]}]}],"version":["1.11.1"],"timestamp":["2012-03-14T06:41:42.600Z"]}]}
  </code></pre>
  
  <p>Important!
  If i change GLOBAL-ID on EBAY-DE, for example, everything is OK! What's wrong with EBAY-US?!</p>