Add OKPAY payment processor to PHP Script

I have a PHP script. It has already other payment processors integrated. I need OKPay ([login to view URL]) payment processor in it. This payment processor will work similar to other payment processors of the script. Who have done a similar work will find it easy. [1] First visit [login to view URL] and see there PHP API then apply to this job only if you feel comfortable to do this job. [2] Write "i have visited [login to view URL] and there PHP API". Applications without this statement will be ignored.