Shopkeeper - Authorize.Net snippet

<?php
global $modx;
 $base_dir = $modx->config['rb_base_dir'];

  $dbname = $modx->db->config['dbase'];
  $dbprefix = $modx->db->config['table_prefix'];
  $mod_table = $dbprefix."manager_shopkeeper";
  $mod_config_table = $dbprefix."manager_shopkeeper_config";
  $reportTpl = $_SESSION['reporttpl'] ? $_SESSION['reporttpl'] : $fields['reportTpl'];
  $userLogged =  isset($_SESSION['webValidated']) ? true : false;

    //Get online payment info
    $order_id = $_SESSION['shk_order_id'];
    $fields['payment'] = $_SESSION['shk_payment_method'];
    $price = $_SESSION['shk_order_price'];
    $currency = $_SESSION['shk_currency'];
    $userId = $_SESSION['shk_order_user_id'];
    $order_email = $_SESSION['shk_order_user_email'];

  require_once $base_dir."snippets/payment/PaymentGateway.php";
  require_once $base_dir."snippets/payment/Authorize.php";


	// Create an instance of the authorize.net library
	$myAuthorize = new Authorize();
	
	// Specify your authorize.net login and secret
	$myAuthorize->setUserInfo('YOUR_LOGIN', 'YOUR_KEY');
	
	// Specify the url where authorize.net will send the user on success/failure
	$myAuthorize->addField('x_Receipt_Link_URL', 'http://www.google.com');
	
	// Specify the url where authorize.net will send the IPN
	$myAuthorize->addField('x_Relay_URL', 'http://www.google.com/working_on_this_part');
	
	// Specify the product information
	$myAuthorize->addField('x_Description', "Online order from " . $modx->config['site_name']);
	$myAuthorize->addField('x_Amount', $price);
	$myAuthorize->addField('x_Invoice_num', $order_id);
	$myAuthorize->addField('x_Cust_ID', $order_email );


// passing customer info
	$myAuthorize->addField('x_first_name', $_SESSION['shk_order_user_fname']);
	$myAuthorize->addField('x_address', $_SESSION['shk_order_user_address']);
	$myAuthorize->addField('x_city', $_SESSION['shk_order_user_city']);
	$myAuthorize->addField('x_state', $_SESSION['shk_order_user_state']);
	$myAuthorize->addField('x_email', $_SESSION['shk_order_user_email']);

	
	// Enable test mode if needed
	$myAuthorize->enableTestMode();
	
	// Let's start the train!
	$myAuthorize->submitPayment();


  return true;
?>

// customer payment information

      $_SESSION['shk_order_user_fname'] = $fields['name'];
      $_SESSION['shk_order_user_address'] = $fields['address'];
      $_SESSION['shk_order_user_city'] = $fields['city'];
      $_SESSION['shk_order_user_state'] = $fields['state'];
// end add on