You do have the ability to modify the code yourself, but this is not setup for a quick and easy addition of a different payment option. Others have done it, but it would take a good amount of work. You could also contact us for a custom project and maybe we can assist you with this.
Our payment gateway has been designed to integrate with zen-cart and other open source applications.
Based on your understanding of Joomla and DT register, do you think this modification would be difficult for our team?
Do we need to purchase the developer edition in order to play with payment scripts? If so, would you at least open a thread for developer subscribers to discuss payment gateway adaptations?