Custom payment gateway

Hi,

I need to create a payment gateway in ecommerce isotope. Payment Gateway is http://www.masterpayment.com. I have instructions from them, but I do not know how I do it.

http://www.masterpayment.com/public/docs/api.pdf
http://www.masterpayment.com/public/docs/examples.zip

Can you help me?

Thank you

Does anyone know to create?
How much would it cost?

Thank you

I also need to do the payment integration with Master Payment . Kindly let me know if any one done it.