apache soap と　.net　での webservice実現方法について

using System;
using System.IO;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Text;

namespace fumiakiy {
  public class Evoxtension : SoapExtension {
    private Stream instr, outstr;
    public override Stream ChainStream(Stream stream) {
      outstr = stream;
      instr = new MemoryStream();
      return instr;
    }
  
    public override object GetInitializer(Type serviceType)  { return null; }
    public override object GetInitializer(
        LogicalMethodInfo methodInfo, 
        SoapExtensionAttribute attribute) { return null; }
    public override void Initialize(object initializer) {}
  
    public override void ProcessMessage(SoapMessage message) {
      StreamReader r;
      StreamWriter w;
      StringBuilder sb;
      switch(message.Stage) {
        case SoapMessageStage.BeforeDeserialize:
          r = new StreamReader(outstr);
          w = new StreamWriter(instr);
          sb = new StringBuilder(r.ReadToEnd());
          sb.Replace("1999", "2001");
          sb.Replace("ur-type", "anyType");
          w.Write(sb.ToString());
          w.Flush();
          instr.Position = 0;
          break;
        case SoapMessageStage.AfterSerialize:
          r = new StreamReader(instr);
          w = new StreamWriter(outstr);
          sb = new StringBuilder(r.ReadToEnd());
          sb.Replace("2001", "1999");
          sb.Replace("anyType", "ur-type");
          w.Write(sb.ToString());
          w.Flush();
          instr.Position = 0;
          break;
        default:
          break;
      }
    }
  }

  [AttributeUsage(AttributeTargets.Method)]
  public class EvoxtensionAttribute : SoapExtensionAttribute {
    private int priority;
    public override Type ExtensionType {
      get { return typeof(Evoxtension); }
    }
    public override int Priority {
      get { return priority; }
      set { priority = value; }
    }
  }
}

[System.Web.Services.Protocols.SoapRpcMethodAttribute(
    "urn:hoge/e", RequestNamespace="urn:hoge", 
    ResponseNamespace="urn:hoge")]
[fumiakiy.Evoxtension()]
public object[] e() {
  object[] results = this.Invoke("e", new object[0]);
  return ((object[])(results[0]));
}