ConfigSetter.cs

        private void SetConfigFile(Dictionary<string, string> configParams, string sid)
        {
            Configuration cfg = WebConfigurationManager.OpenWebConfiguration("/");
            var destinationConfigurationSection = cfg.GetSection("SAP.Middleware.Connector/ClientSettings/DestinationConfiguration");
            var destinationConfigurationType = typeof(RfcDestination).Assembly.GetType("SAP.Middleware.Connector.RfcDestinationConfiguration");
            var destinationCollectionType = typeof(RfcDestination).Assembly.GetType("SAP.Middleware.Connector.RfcDestinationCollection");
            var destinationParametersType =
                typeof(RfcDestination).Assembly.GetType("SAP.Middleware.Connector.RfcDestinationParameters");
            BindingFlags bindFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic |
                                     BindingFlags.Static;
            PropertyInfo destinationsProperty = destinationConfigurationType.GetProperty("Destinations", bindFlags);
            var destinations = destinationsProperty.GetValue(destinationConfigurationSection);
            MethodInfo addMethod = destinationCollectionType.GetMethod("Add", bindFlags, null, new[] { typeof(ConfigurationElement) }, null);
            object destinationParameters =
                Activator.CreateInstance(destinationParametersType, sid);
            foreach (var configParam in configParams)
            {
                PropertyInfo clientProperty = destinationParametersType.GetProperty(configParam.Key, bindFlags);
                clientProperty.SetValue(destinationParameters, configParam.Value);
            }

            addMethod.Invoke(destinations, new[] {destinationParameters});
            cfg.Save(ConfigurationSaveMode.Modified);
        }