title: Flow for: fill form, make paypal payment, create account
body: <p>I've implemented a paypal transaction before but this one has a twist that I'm not quite sure what's the best way to handle it. </p>
  
  <p>The basic idea is I want to create an account for the user when he provides some details and makes a payment via PayPal. Until BOTH the user details are filled out correctly AND the payment is made correctly, I shouldn't create an account for the user.</p>
  
  <p>The setup I've done before was simply a paypal button that the user clicks, makes a payment, and gets forwarded back to just a generic page "your order will be processed and shipped" so there was no pre-order form involved. </p>
  
  <p>This one is different though because</p>
  
  <ul>
  <li>before PayPal, I need to collect initial user data</li>
  <li>after PayPal, I need to create the new user account and use in it the user data collected from the pre-paypal form</li>
  </ul>
  
  <p>I'm sure there's a logical way to implement this, but I'm not quite sure what's the flow I should follow to do it.</p>
  
  <p>I use the Zend framework by the way, which shouldn't matter but just in case Zend has an easier way to help me with what I'm trying to do.</p>