title: Magento Invoice sendEmail() with PDF attachment
body: <p>I use the following code to load an invoice and send email programatically:</p>
  
  <pre><code>&lt;?php
     $invoice = Mage::getModel('sales/order_invoice')
     -&gt;loadByIncrementId($invoice_queue['increment_id']);
     if (null !== $invoice-&gt;getId()){
        $invoice-&gt;sendEmail();
        echo "- Done Invoice #". $invoice_queue['increment_id'] ."\r\n";
     }
     $invoice = null;
  ?&gt;
  </code></pre>
  
  <p>This appears to be sending the invoice email correctly. However, the PDF attachment of the invoice isn't there in the email.</p>
  
  <p>If I were to send the email via magento, it works.</p>
  
  <p>Any idea how to get the PDF to be attached, when calling <strong>sendEmail()</strong> function?</p>