Creating gateways is a very time consuming process. First you need to get a test account with the payment gateway company in question, then their documentation and if you're lucky it's in English. Then you need to thoroughly read the documentation to make sure you fully understand the hoops that their system makes you jump through, and finally create test and support the gateway.
I actually enjoy making gateways for you, you need to pay for the any new gateway which is not list in our support. At last count they have already put together 6 different gateways and banks for Bookpro.
3. Mellat bank