Webmoney IPN Integration to webshop

We are looking for someone knowledgeable with PHP and SQL to customize our existing PHP-Script for our website that is capable of automatically deliver pre-created serial keys / Voucher-Codes to our customers via e-mail. The script just needs some adjustments to work with our new payment gateway "Webmoney". I had come up with a possible solution myself, but it doesn't seem stable enough and I would prefer a more professional approach. This is a really simple project, a script really, so I don't have a large budget in mind for it. Please feel free to message me with any questions.