Problem z SendMessage

Witam, mam problem prawdopodobnie z funkcją SendMessage. Otóż problem polega na tym, że dla 1 buttona działa wszystko poprawnie. Natomiast dla kolejnych już nie.

    Declare Auto Function FindWindow Lib "USER32.DLL" (
    ByVal lpClassName As String,
    ByVal lpWindowName As String) As IntPtr

    Declare Auto Function SendMessage Lib "USER32.DLL" (
    ByVal hWnd As IntPtr,
    ByVal Msg As UInteger,
    ByVal wParam As IntPtr,
    ByVal lParam As IntPtr) As Integer

    Declare Auto Function FindWindowEx Lib "USER32.DLL" (
    ByVal hwndParent As IntPtr,
    ByVal hwndChildAfter As IntPtr,
    ByVal lpszClass As String,
    ByVal lpszWindow As String) As IntPtr

    Private Const BM_CLICK As Integer = &HF5

    Declare Auto Function SetForegroundWindow Lib "USER32.DLL" (
    ByVal hWnd As IntPtr) As Boolean

        Dim hwnd As IntPtr = FindWindow("TKlawisze", vbNullString)
        Dim hwndFrame As IntPtr = FindWindowEx(hwnd, Nothing, "Tpanel", Nothing)
        Dim hwndDialog As IntPtr = FindWindowEx(hwndFrame, Nothing, "Tpanel", Nothing)
        Dim hwndDialog1 As IntPtr = FindWindowEx(hwndFrame, hwndDialog, "Tpanel", Nothing)
        Dim hwndDialog2 As IntPtr = FindWindowEx(hwndFrame, hwndDialog1, "TPanel", Nothing)
        Dim hWndButton As IntPtr = FindWindowEx(hwndDialog2, Nothing, "TButton", ">>")

        SetForegroundWindow(hWndButton)
        SendMessage(hWndButton, BM_CLICK, 0, 0)

Powyższy kod działa poprawnie. Jeśli jednak zmienię hWndButton na inny, nie ma "klinięcia" obiektu.

Dim hWndButton As IntPtr = FindWindowEx(hwndDialog2, Nothing, "TPanel", "USTAW BAZĘ")