Alertpay IPN integration and subscription renewal in Perl/cgi-bin script

This script is already configured to upgrade members after payment but they have to enter their username and Alertpay account for the system to update them. What I need is the Alertpay IPN integrated in the script so after payment members will be upgraded automatically without the need to fill out the form first. Because the membership fee is a recurring fee I need a little modification that will allow me to renew subscriptions after members have paid the recurring fee. When I renew the subscription all affiliates need to receive their commission again (it's a multi level affiliate program). There already is an option to add commission to accounts but it needs to be automated when I renew a subscription so all affiliates will receive their recurring commission again. I have a demo ready to see the admin area to understand how the script works if needed.