动态调用webservice时怎么验证身份

动态调用webservice时如何验证身份？
原文：http://www.cnblogs.com/RainWaterLily/archive/2008/01/27/1055099.html
的确很牛，可以实现动态调用webservice。但有个问题：如何设置身份验证？哪位达人可以告知，谢谢！
VB中实现的代码如下：
定义个类：clsSoapHeaderHandler

Implements IHeaderHandler
Option Explicit

'used for verification in webservice
Public AuthUser As String 'user name
Public AuthPassword As String 'user password
Private Function IHeaderHandler_readHeader(ByVal par_Reader As MSSOAPLib30.ISoapReader, ByVal par_HeaderNode As MSXML2.IXMLDOMNode, ByVal par_Object As Object) As Boolean
  IHeaderHandler_readHeader = False
End Function
Private Function IHeaderHandler_WillWriteHeaders() As Boolean
  IHeaderHandler_WillWriteHeaders = True
End Function
Private Sub IHeaderHandler_writeHeaders( _
  ByVal pSerializer As SoapSerializer30, _
  ByVal pObject As Object)

  'generate SOAP XML request message
  pSerializer.StartHeaderElement "Authentication", "http://www.ibm.com"

  pSerializer.StartElement "Username" 'Matching with SERVICE code
  pSerializer.WriteString AuthUser
  pSerializer.EndElement

  pSerializer.StartElement "Password"
  pSerializer.WriteString AuthPassword
  pSerializer.EndElement

  pSerializer.EndHeaderElement
End Sub

调用的地方：

dim objHeaderHandler as New clsSoapHeaderHandler
dim mysoapClient as SoapClient30

  objHeaderHandler.AuthUser = "username"
  objHeaderHandler.AuthPassword = "pws"
  Set mysoapClient.HeaderHandler = objHeaderHandler
这样就可以把验证信息传给服务器，动态调用webservice时如何把这段转成C#代码？

------解决方案--------------------
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