title: Magento UPC API
body: <p>What is the Array options for Products.update?  I need to add UPC information to all of my products and I want to build a script to perform this task:</p>
  
  <pre><code>$client-&gt;call($session, 'catalog_product.update', array($product['sku'], 'upc'=&gt;$xml));
  </code></pre>
  
  <p>Its not working because I don't know the UPC - XML=>UPC equivalent.  Any ideas?</p>