title: paypal subscription first IPN txn_type when doing new registeration for subscription
body: <p>I am now testing some IPN for our subscription system.
  from this document <a href="https://www.paypal.com/cgi-bin/webscr?cmd=p/acc/ipn-subscriptions-outside" rel="nofollow">https://www.paypal.com/cgi-bin/webscr?cmd=p/acc/ipn-subscriptions-outside</a>
  the documentation is complete but i need some more confirmation on these..</p>
  
  <ol>
  <li><p>when is the first time paypal will send an IPN when user doing new registration for a subscription?</p></li>
  <li><p>do "amount1" and "amount3" also sent after the first payment?</p></li>
  <li><p>from these combination of parameters in the documentation above. how i can tell that the notification is for a trial payment? or a regular payment or for 1st payment?</p></li>
  </ol>
  
  <p>I cant find a tool for doing subscription IPN test.. even in the paypal sandbox/developer site. i wonder if anybody can suggest me how to easily test these things.</p>