Virtuemart customized payment method using POST

[ferry91]

I'm doing a college project in which I've built a very simple localhost e-commerce website over joomla 2.5.4 and virtuemart 2.0.6. The goal of the subject is to study the security over networks and so, I've been asked to use a payment method in which I directly send the payment information (product, price and credit card nummber) in plaintext using a POST method to a simple website which will process this data. The problem here, is that I do not know how to add a customized payment method in virtuemart. In addition I am not experienced with php. I've been trying to find a free extension that provide a similar funcionality but, I have not found anything useful for me. I guess I will have to program it myself but I'm completely lost at the moment. Any ideas?

Thank you in advance!