WebDav with HttpRequest   

Hi,
I wrote an application(VB.Net) with XmlHttp object (COM) to do some 
operations in the exchange server. This application works fine. Now , I want 
to write the same application with HttpRequest(.Net) instead of XmlHttp, but 
always When I try to get a response from a query, I get the following error :
The remote sever returned an error:(404) Not Found.
Here some lines of the application:

 '***** Save the attachment *******
' sUrlAttach is the url of an attachment in the exchange
        Dim myreq As Net.HttpWebRequest = Net.WebRequest.Create(sUrlAttach)
        myreq.Method = "GET"
        myreq.Credentials = New System.Net.NetworkCredential("****", "*****")
        ' The error occures after this line :
        Dim o_resp As Net.WebResponse = myreq.GetResponse()
        Dim instream As Stream = o_resp.GetResponseStream()
        Dim sr As StreamReader = New StreamReader(instream)
        Dim sResp As String = sr.ReadToEnd()
        Dim fs As New FileStream("C:\" & attchFileName, FileMode.Create)
        Dim w As New StreamWriter(fs)
        w.Write(sResp)
        w.Close()
        fs.Close()

Like I wrote before, This is just one example ,and I have this problem with 
others querys too.

Thanks,

David

date: Sun, 23 Dec 2007 07:33:41 -0800   author:   DavidE