Changes to a PHP script using PayPal IPN

I have a PHP script called ebay assist 1.06( [login to view URL]) that is used for digital downloads via ebay/paypal using IPN. When a user purchases an ebay auction and pays via paypal the user is emailed via IPN with the download URL, username & password. PROBLEM: I already use IPN for another service and need another way for the script to work. Please don't expect me to provide my Paypal information when modifing the script. If you need more information on how the script works, please visit [login to view URL] When replying to this bid, I request: 1. Cost to complete the project 2. What are the possible solutions or work around 3. Timeline The script can be edited per the license holder - please read [login to view URL] Can I remove your "Powered By" link? You are allowed to remove this link if you wish (or better yet, sign up as an iDevSpot Affiliate and use our "Powered By" link to earn a commission on referred visitor sales!). Is your software encoded? Can I edit it? Not it is not, and yes you can! Please let me know if you have any other questions.