Nested Configuration Sections

I'm currently writing a console app that will allow a user to pass a config section name and a command type (ex: start, stop, pause, etc.) to manipulate WCF services. This is my first time writing an app config and I'm having a little trouble getting it to work while also having a readable and sustainable app config that's not going to grow into an ugly beast. Any help in pointing me in the right direction would be greatly appreciated.

Things to note:
1) For any given configuration section, there can be any number of "serviceInstances".

2) I would like to keep the individual serverNames/serviceNames paired to help prevent user error.

Custom Configuration Class

Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;
using log4net;
using ServiceManipulator;
using System.Collections.Specialized;

namespace ServiceManipulator
{
    public class ManipulatorConfiguration //: ConfigurationSection
    {
        private static readonly ILog Log = LogManager.GetLogger(typeof(ManipulatorConfiguration));
        public static readonly string configGroup = "CustomConfigs";
        public string configSection = string.Empty;
        public string commandType = string.Empty;
        public CustomConfiguration configValues;


        /// <summary>
        /// Gets the configuration section settings.
        /// </summary>
        /// <param name="args"></param>The config section and command type</value>
        /// <returns>Configuration of ManipulatorConfiguration type</returns>
        public static ManipulatorConfiguration GetConfiguration(string[] args)
        {
            ManipulatorConfiguration config = new ManipulatorConfiguration();
            Log.Info(string.Format("Retrieving '{0}' configuration section...", config.configSection));

            config.ParseCommandLine(args);
            config.configValues = CustomConfiguration.GetCustomConfigSettings(config.configSection);

            return config;
        }

        /// <summary>
        /// Parses and validates key/value pairs from arguments
        /// </summary>
        /// <param name="args">The config section and command type</param>
        private void ParseCommandLine(string[] args)
        {
            string key = string.Empty;
            string argValue = string.Empty;
            HashSet<string> validCommands = new HashSet<string>();
            validCommands.Add("START");
            validCommands.Add("STOP");
            validCommands.Add("CONTINUE");
            validCommands.Add("PAUSE");

            try
            {
                if (args != null && args.Length == 2)
                {
                    foreach (string arg in args)
                    {
                        key = arg.ToUpper().Trim();
                        argValue = arg.Trim().Substring(arg.Trim().IndexOf(':') + 1).Trim();

                        if (key.StartsWith("CONFIG:") && !string.IsNullOrEmpty(argValue))
                            this.configSection = argValue;
                        else if (key.StartsWith("COMMAND:") && !string.IsNullOrEmpty(argValue) && validCommands.Contains(argValue))
                            this.commandType = argValue;
                        else
                        {
                            Log.Error("One or more user defined arguments are invalid. Exiting console application...");
                            Environment.Exit((int)ManipulatorExitCode.InvalidArguments);
                        }
                    }
                }
                else
                {
                    Log.Error("Config section and command type are required arguments. Exiting console application...");
                    Environment.Exit((int)ManipulatorExitCode.InvalidArguments);
                }
            }
            catch (Exception ex)
            {
                Log.Error("An error occurred while parsing the command line.", ex);
                Environment.Exit((int)ManipulatorExitCode.ConfigLoadError);
            }
        }
    }

    public class CustomConfiguration
    {
        private static readonly ILog Log = LogManager.GetLogger(typeof(ManipulatorConfiguration));
        public static readonly string subSection = "ServiceInstances";

        public static CustomConfiguration GetCustomConfigSettings(string customSectionName)
        {
            CustomConfiguration config = new CustomConfiguration();
            try
            {
                string tempString = @"CustomConfigs/" + customSectionName + '/' + subSection;
                //NameValueCollection manipulatorConfigs = (NameValueCollection)ConfigurationManager.GetSection(tempString);
                NameValueConfigurationCollection manipulatorConfigs = (NameValueConfigurationCollection)ConfigurationManager.GetSection(tempString);
            }
            catch (Exception ex)
            {
                Log.Error(ex.ToString());
                Environment.Exit((int)ManipulatorExitCode.ConfigLoadError);
            }

            return config;
        }
    }
}

Here's the app config setup

Code:

<?xml version="1.0"?>
<configuration>
	<configSections>		
		<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
		<section name="RetrySettings" type="System.Configuration.NameValueSectionHandler"/>
		<section name="ServiceInstances" type="System.Configuration.NameValueSectionHandler"/>
		<sectionGroup name="CustomConfigs">
			<section name="MySection" type="System.Configuration.NameValueSectionHandler"/>
			<section name="AnotherSection" type="System.Configuration.NameValueSectionHandler"/>
		</sectionGroup>
	</configSections>

	<!-- Default Retry Settings. -->
	<RetrySettings>
		<add key="Loops" value="3"/>
		<add key="LoopDelay" value="10"/>
		<add key="EmailOnFailure" value="true"/>
		<add key="EmailOnSuccess" value="false"/>
		<add key="EmailTo" value=""/>
		<add key="EmailFrom" value=""/>
		<add key="EmailSmtpHost" value=""/>
	</RetrySettings>
	
	<!-- Custom Configuration Settings -->
	<CustomConfigs>
		<MySection>
			<ServiceInstances>
				<add key="serverName" value="ServiceNameHere"/>
                <add key="ServerName2" value="ServiceName"/>
                <add key="ServerName3" value="ServiceName"/>
			</ServiceInstances>
		</MySection>
		<AnotherSection>
			<ServiceInstances>
				<add key="ServerName" value="ServiceName"/>
				<add key="ServerName4" value="ServiceName"/>
				<add key="ServerName5" value="ServiceName"/>
			</ServiceInstances>
			<!-- Example of overriding the default retry settings.
			<RetrySettings>
				<add key="EmailOnFailure" value="false"/>
			</RetrySettings>
			-->
		</AnotherSection>
	</CustomConfigs>
	
	<!-- Logging Configuration -->
	<log4net debug="false">
		<appender name="LogFileAppender" type="log4net.Appender.RollingFileAppender">
			<file value="ServiceManipulator.log"/>
			<rollingStyle value="Date"/>
			<maxSizeRollBackups value="10"/>
			<staticLogFileName value="true"/>
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%date{yyyy/MM/dd HH:mm:ss} %-5level %logger [%thread] %method &lt;%mdc{auth}&gt; - %message%newline"/>
			</layout>
		</appender>
		<appender name="ConsoleAppender" type="log4net.Appender.ColoredConsoleAppender">
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%-5leve - %message%newline"/>
			</layout>
			<mapping>
				<level value="ERROR"/>
				<foreColor value="White"/>
				<backColor value="Red, HighIntensity"/>
			</mapping>
			<mapping>
				<level value="DEBUG"/>
				<foreColor value="White"/>
				<backColor value="Green"/>
			</mapping>
			<mapping>
				<level value="INFO"/>
				<foreColor value="White"/>
				<backColor value="Blue"/>
			</mapping>
			<mapping>
				<level value="WARN"/>
				<foreColor value="Blue"/>
				<backColor value="Yellow, HighIntensity"/>
			</mapping>
		</appender>
		<appender name="EventLogAppender" type="log4net.Appender.EventLogAppender">
			<threshold value="ERROR"/>
			<logName value="GEDI"/>
			<applicationName value="ServiceManipulator"/>
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%date{yyyy/MM/dd HH:mm:ss} [%thread] %-5level %logger %message%newline"/>
			</layout>
			<mapping>
				<level value="FATAL"/>
				<eventLogEntryType value="Error"/>
			</mapping>
			<mapping>
				<level value="ERROR"/>
				<eventLogEntryType value="Error"/>
			</mapping>
			<mapping>
				<level value="WARN"/>
				<eventLogEntryType value="Warning"/>
			</mapping>
			<mapping>
				<level value="INFO"/>
				<eventLogEntryType value="Information"/>
			</mapping>
			<mapping>
				<level value="DEBUG"/>
				<eventLogEntryType value="Information"/>
			</mapping>
		</appender>
		<!-- Setup the root category to log everything to the rolling file appender-->
		<!-- SET TO "INFO" for deployment -->
		<root>
			<priority value="DEBUG"/>
			<appender-ref ref="EventLogAppender"/>
			<!--<appender-ref ref="ConsoleAppender" />-->
			<appender-ref ref="LogFileAppender"/>
		</root>
	</log4net>
<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/></startup></configuration>