[win32] - button super class and BS_NOTIFY

i'm building the button class and the button is showed and the button messages(WM_CREATE and others) works... but why i can't use the BN messages(included the WM_COMMAND message)?
i use the BS_NOTIFY when i create the button... so what wrong with these message procedure?

Code:

---

case WM_COMMAND:
            {
                MessageBox(hwnd,TEXT("hello"),TEXT("hi"),MB_OK);

            }
            break;

---

so why i didn't get the WM_COMMAND message?