Payment Gateway Setup (Payfast)

Overview
Please follow the instructions below to activate this gateway. If the payment gateway's interface has changed or if the screenshots (where applicable) look different, please let me know.
Payfast - Setup
1: Sign up for a Payfast account to receive your merchant information.
2: Enter applicable details in your Maian Cart admin area:

Sales > Payment Methods > Payfast
Payfast - Callback Url
The callback url for all operations is:

http://www.example.com/checkout/payfast.php
https://www.example.com/checkout/payfast.php (SSL)

Where 'example.com' is your own domain.
Payfast - Sandbox
Payfast has a test sandbox system to test payments. For the sandbox system to kick in, you need to use the following:

Merchant Account
Username: sbtm01@payfast.co.za
Merchant ID: 10000100
Merchant Key: 46f0cd694581a

User Account
Username: sbtu01@payfast.co.za
Password: clientpass