WTL : sublclassing and gettins Btn msg

Hi,

I know it's not a WTL newsgroup but generally people writing MFC has
also a knwoledge of WTL.
I have a simple Dialog Class defined like this :

class CMainDlg : public CDialogImpl<CMainDlg>,
                     public CWinDataExchange<CMainDlg>
{
public:

     BEGIN_MSG_MAP(CMainDlg)
         MESSAGE_HANDLER(WM_INITDIALOG, OnInitDialog)
         COMMAND_ID_HANDLER(IDOK, OnCloseCmd)
         COMMAND_ID_HANDLER(IDCANCEL, OnCloseCmd)
          ALT_MSG_MAP(1)
         MSG_WM_LBUTTONDOWN(OnUpdateBtn)
     END_MSG_MAP()

     enum { IDD = IDD_MAINDLG };

     CMainDlg::CMainDlg() :
     m_wndUpdateBtn(this, 1){}

     virtual BOOL PreTranslateMessage(MSG* pMsg)
     {
         return ::IsDialogMessage(m_hWnd, pMsg);
     }
     LRESULT OnInitDialog(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM
/*lParam*/, BOOL& bHandled)
     {
         return bHandled = FALSE;
     }

     LRESULT OnCloseCmd(WORD /*wNotifyCode*/, WORD wID, HWND
/*hWndCtl*/, BOOL& /*bHandled*/)
     {
         EndDialog(wID);
         return 0;
     }

     LRESULT OnUpdateBtn(HWND hwndCtrl, UINT uHitTest, UINT uMouseMsg)
     {
         ::MessageBox(NULL, _T("fdfsdf"), _T(""), 0);
         return 0;
     }

protected:
     CContainedWindow m_wndUpdateBtn;
};

But when i click on my Update Btn nothings happens.

Any idea ?

I know that with WTL you have different ways of getting message and
subclassing controls and I would like the one with CContainedWindow
that looks like MFC