how to use PROXY in CLIENT

proxy

Dim ObjProxy As New System.Net.WebClient
Dim prxy As New WebProxy(My.Settings.Proxy_Server, Integer.Parse(My.Settings.Proxy_Port))
prxy.Credentials = New NetworkCredential(My.Settings.Proxy_User, My.Settings.Proxy_Password, My.Settings.Proxy_Domain)
ObjProxy.Proxy = prxy

by using the above code, able to create proxy, but do not how to use the above proxy to the below client.

  Using client = New EndUserClient("defaultEP_EU")
                Using scope = New OperationContextScope(client.InnerChannel)
                    Dim header = MessageHeader.CreateHeader("Username", "hc", Username)
                    OperationContext.Current.OutgoingMessageHeaders.Add(header)
                    header = MessageHeader.CreateHeader("Password", "hc", Password)
                    OperationContext.Current.OutgoingMessageHeaders.Add(header)
                    If client.Ping() Then
                        ' Dim NewUserId As Object = client.GetUserByUsername(mob)
                        Dim subcheck As New EndUser
                        subcheck = client.GetUserByUsername(mob)
                    End If
                End Using
            End Using