title: Paypal IPN call back with parameter
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/2847114/can-i-send-a-variable-to-paypal-and-have-it-post-it-back-to-me-when-payment-comp">Can I send a variable to paypal, and have it post it back to me when payment completes?</a>  </p>
  </blockquote>
  
  
  
  <p>I want to automate a process after user have made a payment.</p>
  
  <p>1) User enter details on forms and submit, the session will pass unique ID to paypal
  2) After user complete the paypal payment, unique ID is then pass back to my server for the script to read and register into db.</p>
  
  <p>How do I do that?</p>