Authorize.net script integrated into Smarty Template

Custom Smarty Site I already have Paypal integrated & a few other payment gateways. I need [login to view URL] integrated with the same payments verification steps as the other payment gateways already in place. The user does not receive there coupon without verification that payment has been accepted and approved. I will also have other small additions that will be needed. Must communicate daily and also sign a non-disclosure prior to starting work.