title: Magento API v2 filter by custom attribute
body: <p>I've been looking all over the web but I can't seem to find any examples and I've tried it but failed. I am using version 2 of the api and I want to find product that filters by a customer attribute like so...</p>
  
  <pre><code>$filter = array(
          array(
              'key'=&gt;'custom_attribute',
              'value'=&gt;"463"
          )
  );
  $products = $client-&gt;catalogProductList($session,array(
      'filter'=&gt;$filter
  )); 
  </code></pre>
  
  <p>But I am getting all the products and not the specific product I am looking for. Is there anything I am doing wrong ? Is there anything  I am missing ?? </p>