oShape = oSlide.Shapes.AddShape( _
  Microsoft.Office.Core.MsoAutoShapeType.msoShapeActionButtonCustom, 30, 480, _
  105, 30)
 
                oShape.ActionSettings( _
                  Microsoft.Office.Interop.PowerPoint.PpMouseActivation.ppMouse_
                  Click).Action = PowerPoint.PpActionType.ppRunMacro
 
oShape.ActionSettings(PowerPoint.PpMouseActivation.ppMouseClick).Run = "Test"
 
...
 
    Sub Test()
 
        MsgBox("hallo")
    End Sub