Webservice in IFS Test 10

Hi there, I am currently integrating the IFS web service into VB.Net. Now my first query does not work, however, the session is terminated here. What am I doing wrong?

    Private Sub Button_Click(sender As Object, e As RoutedEventArgs)

        Dim TestOrder As IFS_TestSystem.testOrder = New IFS_TestSystem.testOrder

        TestOrder.customerId = "11804"
        TestOrder.orderNo = "2461601"

        Dim GetTestorder As Test_IFSWebservices.IFS_TestSystem.BptestOrderInteractionService = New IFS_TestSystem.BptestOrderInteractionService
        Dim returningorder As IFS_TestSystem.testOrder = GetTestorder.getTestOrder(TestOrder)

    End Sub

Where I can find an example in C# or VB.Net?

Thanks