What you can do is call it like this for a dialog button:
HWND hWnd, // handle to window
BOOL bEnable // flag for enabling or disabling input
Identifies the window to be enabled or disabled.
Specifies whether to enable or disable the window. If this parameter is TRUE, the window is enabled. If the parameter is FALSE, the window is disabled.
If the window was previously disabled, the return value is nonzero.
If the window was not previously disabled, the return value is zero. To get extended error information, call GetLastError.