We have been working on integrating the IPN or Instant Payment Notifications for one our Client.
We saw that the IPN Simulator supports for only some Transaction Types, and our chosen Types are for Donate and Subscription which are currently not supported.
So we had to create a PayPal Buttons for the both in Sandbox with IPN URL Setup, and then use the same for doing the IPN Testing as given in the Testing Guide of IPN.
We were able to get the Payload with amount, tax, buyer email id, etc, but couldn't get the txn_id field, without which we cannot know for sure whether the customer has payed his amount or not and also for book keeping in our DB Servers.
Please help us as to where we might have gone wrong ?
We have seen a lot of help sites, but none of them give us conclusive steps to get this issue fixed.