VB.NET SetDataOnSimObject

Hi, Does anyone know how to use SetDataOnSimObject function in VS2005 to change my plane's airspeed and altitude. I am just modifying Managed VB.NET Code Sample to read data from FSX but I wish to set data to fsx.Such as I want to create a button that can set my airspeed to 250 immediately. I tried to put below into Private Sub initDataRequest() of the sample: Dim pos As Microsoft.FlightSimulator.SimConnect.SIMCONNECT_DATA_INITPOSITION pos.Altitude = 3500 pos.Airspeed = 30 fsx_simconnect.SetDataOnSimObject(StructDefinitions.Struct1, SimConnect.SIMCONNECT_OBJECT_ID_USER, SIMCONNECT_DATA_SET_FLAG.DEFAULT, pos)It didn't work. Thankyou.