Enumerating children problem

So I'm trying to find a radio button in a window.

I'm using enumerate children function with the following function as processor:

LONG style;
	style = GetWindowLong(hwnd, GWL_STYLE);
	if(style==BS_AUTORADIOBUTTON){
		MessageBox(NULL,"RADIO","",NULL);
		PostMessage(hwnd, BM_SETCHECK, BST_CHECKED, 0);
	}
	return TRUE ;

I checked with spy++,there is a radio button with that style,however the msgbox never appears,why?