How access Custom Order Data added when purchase made through Custom payment gateway

While taking an order through my CMSPaymentGatewayForm (Custom Payment gateway), I add a few custom data items, and I can't seem to see where I can retrieve the data later through the API. Any ideas?

Here is how I add the data:

 public override string ProcessData()
   {
   ...
                        PaymentGatewayCustomData["ChurchAccount"] = ChurchAccount.Text;
                        PaymentGatewayCustomData["ChurchPin"] = ChurchPIN.Text;
                        PaymentGatewayCustomData["ChurchName"] = reader["ChurchName"];
                        CMS.Ecommerce.PaymentResultItemInfo itemInfo = new CMS.Ecommerce.PaymentResultItemInfo();
                        itemInfo.Name = "Church Account";
                        itemInfo.Text = "Verified";
                        CMS.Ecommerce.OrderInfo orderInfo = new CMS.Ecommerce.OrderInfo();
                        orderInfo.OrderPaymentResult.SetPaymentResultItemInfo(itemInfo);
                        return string.Empty;
                    }
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }

        }