PayPal.SOAP.MerchantAPICallPreHandler.GetPayloadUsingSOAPHeader C# (CSharp) Method

        private string GetPayloadUsingSOAPHeader(string payload, string namespaces, string header)
        {
            string returnPayload = null;
            Regex regex = new Regex("\\{(?![01]})");
            string formattedPayload = regex.Replace(payload, "{{");
            regex = new Regex("(?<!\\{[01]{1})}");
            formattedPayload = regex.Replace(formattedPayload, "}}");
            returnPayload = string.Format(formattedPayload, new object[] { namespaces, header });
            return returnPayload;
        }