title: Not loading product by custom attribute
body: <p>I have a custom attribute that I created, but for some reason when I try to get the product by reference, I get the first product of the products collection and not the specific product. Am I doing something wrong, all the examples have the loadAttribute by SKU and it works, but when i use other attribute beside SKU it doesn't work. Any idea of the issue?</p>
  
  <pre><code>require '../../app/Mage.php';
  umask(0);
  Mage::app();
  Mage::register('isSecureArea', 1);
  
  
  $_product = Mage::getModel('catalog/product')-&gt;loadByAttribute('reference','F1515101');
  </code></pre>