title: How can I pass Paypal ipn custom and invoice variables?
body: <p>I'm trying to use the paypal ipn to pass variables from when the user clicks on my button to when I get the ipn notification.  I'm currently testing this on the sandbox.  I get the IPN request just fine, but when it comes in, it is missing the two variables, custom and invoice, that I passed on the form.  This is an example of what my form looks like:</p>
  
  <pre><code>&lt;form id="paypal-form" action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post"&gt;
     &lt;input type="hidden" name="cmd" value="_s-xclick"/&gt;
     &lt;input type="hidden" name="hosted_button_id" value="23424234488"/&gt;
     &lt;input type="hidden" name="custom" value="basic"/&gt;
     &lt;input type="hidden" name="invoice" value="24817238724"/&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>When I get the IPN, custom and invoice are not defined on the request.  How can I get these values to pass through?</p>