Hello,
you should read about cURL [php.net] about post variables via SSL and PHP This is just a simple code, I using to connect to authorize.net
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$ch=curl_init("https://secure.authorize.net/gateway/transact.dll");
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_POSTFIELDS, $fields); // set the fields to post
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); // make sure we get the response back
$buffer = curl_exec($ch); // execute the post
curl_close($ch); // close our session
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At the $fields, you should put all of your variables.
At $buffer you will have the results or the server output.
Note, your server must support cURL functions and the PHP must be compilied with curl.