Visual Basic.NET - Simular eventos del mouse y del teclado

Hola, este programa simula un enter dando doble click con el mouse, me ayudarian mucho si pudiesen decirme como aplicar este programa al Messenger, mi computadora está en Español México. Se que el evento secundario está paraque funcione en la calculadora, pero no lo quiero para la calculadora si no para Messenger. ¿Podrían decirme donde debo modificarle? Gracias.

Imports System
Imports System.Runtime.InteropServices
Imports System.Drawing
Imports System.Windows.Forms

Namespace SimulateKeyPress

Class Form1
Inherits Form
Private WithEvents button1 As New Button()

<STAThread()> _
Public Shared Sub Main()
Application.EnableVisualStyles()
Application.Run(New Form1())
End Sub

Public Sub New()
button1.Location = New Point(10, 10)
button1.TabIndex = 0
button1.Text = "Click to automate Calculator"
button1.AutoSize = True
Me.Controls.Add(button1)
End Sub

' Get a handle to an application window.
Declare Auto Function FindWindow Lib "USER32.DLL" ( _
ByVal lpClassName As String, _
ByVal lpWindowName As String) As IntPtr

' Activate an application window.
Declare Auto Function SetForegroundWindow Lib "USER32.DLL" _
(ByVal hWnd As IntPtr) As Boolean

' Send a series of key presses to the Calculator application.
Private Sub button1_Click(ByVal sender As Object, _
ByVal e As EventArgs) Handles button1.Click

' Get a handle to the Calculator application. The window class
' and window name were obtained using the Spy++ tool.
Dim calculatorHandle As IntPtr = FindWindow("SciCalc", "Calculator")

' Verify that Calculator is a running process.
If calculatorHandle = IntPtr.Zero Then
MsgBox("Calculator is not running.")
Return
End If

' Make Calculator the foreground application and send it
' a set of calculations.
SetForegroundWindow(calculatorHandle)
SendKeys.SendWait("111")
SendKeys.SendWait("*")
SendKeys.SendWait("11")
SendKeys.SendWait("=")
End Sub

' Send a key to the button when the user double-clicks anywhere
' on the form.
Private Sub Form1_DoubleClick(ByVal sender As Object, _
ByVal e As EventArgs) Handles Me.DoubleClick

' Send the enter key to the button, which raises the click
' event for the button. This works because the tab stop of
' the button is 0.
SendKeys.Send("{ENTER}")
End Sub

End Class
End Namespace