LogSoapModule

using System;
using System.Text;
using System.Web;
using NLog;

namespace Choco.Shared.Web.App_Start
{
	public class LogSoapModule : IHttpModule
	{
		public void Init(HttpApplication context)
		{
			context.BeginRequest += this.OnBegin;
		}

		private void OnBegin(object sender, EventArgs e)
		{
			var context = ((HttpApplication) sender).Context;

			var innerLogger = LogManager.GetLogger("incomingRequest");
			innerLogger.Info(context.Request.Url);

			if (!innerLogger.IsTraceEnabled)
				return;

			byte[] buffer = new byte[context.Request.InputStream.Length];
			context.Request.InputStream.Read(buffer, 0, buffer.Length);
			context.Request.InputStream.Position = 0;

			string soapMessage = Encoding.ASCII.GetString(buffer);

			if (!string.IsNullOrEmpty(soapMessage))
				innerLogger.Trace(soapMessage);
		}

		public void Dispose()
		{
			//
		}
	}
}

web.cofig

<system.webServer>
	<modules runAllManagedModulesForAllRequests="true">
		<add name="LogSoapModule" type="Choco.Shared.Web.App_Start.LogSoapModule" />
	</modules>
</system.webServer>