Payment notification function

I am currently developing a multi seller site using Drupal 5.20, Ubercart 5.x-1.8 and Ubercart Marketplace 5.x-1.0-beta5

My site is using mass payment method and I plan to use a local payment gateway from Malaysia (NBePay). I need a function which can get the Return Parameter from the payment gateway and generate a payment notification email to sellers.

Sample of this function can be found in X-Cart, refer to attachment.

API Specification for NBePay Integration can be downloaded at http://chiewfan.com/documents/NBePay_Spec-v9_5.pdf

Thanks.