Here is solution!
Public Shared Function CallWebService(ByVal an As String, ByVal xmlcommand As String) As String
Dim _url = "http://testapi.interface-xml.com/appservices/ws/FrontendService"
Dim soapEnvelopeXml As XmlDocument = CreateSoapEnvelope(xmlcommand)
Dim webRequest As HttpWebRequest = CreateWebRequest(_url, an)
webRequest.Proxy = System.Net.WebRequest.DefaultWebProxy
webRequest.Headers.Add("Accept-Encoding", "gzip, deflate")
InsertSoapEnvelopeIntoWebRequest(soapEnvelopeXml, webRequest)
Dim asyncResult As IAsyncResult = webRequest.BeginGetResponse(Nothing, Nothing)
asyncResult.AsyncWaitHandle.WaitOne()
Dim soapResult As String
Using webResponse As WebResponse = webRequest.EndGetResponse(asyncResult)
Using bs As New BufferedStream(webResponse.GetResponseStream())
Using gz As New GZipStream(bs, CompressionMode.Decompress)
Using rd As New StreamReader(gz)
soapResult = rd.ReadLine()
Return soapResult
End Using
End Using
End Using
End Using
End Function