title: Magento - updating orders and customer notification
body: <p>Within Magento orders, there is the option to send the customer a notification to update them of the status</p>
  
  <p>I have some orders that <code>Processing</code>, but i cannot seem to update them to any other status.</p>
  
  <p>I'd like to add custom status's so I can send the customer a notification.</p>
  
  <p>In the drop down i could select <code>Warehouse</code>, which would notify the customer their order is in the warehouse</p>
  
  <p>How would I do this?</p>
  
  <p>I'm using v1.6.2</p>
  
  <p>Thanks</p>