Send shipping address into Authorize.net

[PfftD]

I have implemented the Authorize.net payment method in my web site. I have sent the billing info and payment into to the autorize.net. But I want to send the shipping information too. I am using the following code\[code\]"x_first_name" => $firstname,"x_last_name" => $lastname,"x_address" => $bill_address,"x_city" => $bill_city,"x_state" => $bill_state,"x_zip" => $bill_zip,"x_country" => $bill_country,"x_phone" => $phone,\[/code\]Using curl to send the data.Does any one know how to send the shipping info?Thanks in advance