How can I refresh windows mobile to change backlight?

I am trying to change the brightness of PPC by modifying registry value through code.
KEY: HKEY_CURRENT_USER\ControlPanel\BackLight
DWORD: ACBrigthness = 5
It's working. But, I can see the change after restarted only (soft reset) . I want to see the effect without restart PPC. How can i do this?
I tried below code also....
//To change the registry
HKEY_CURRENT_USER, L"ControlPanel\\BackLight", L"ACBrigthness", value
i am using the below code to refresh the pocket pc.
HANDLE hld = CreateEvent(NULL, FALSE, TRUE,TEXT("BackLightChangeEvent"));
if (hld)
{
SetEvent(hld);
CloseHandle(hld);
}
SendMessage(HWND_BROADCAST, WM_SETTINGCHANGE, NULL,NULL);

But, it's not working what i am doing wrong.. can you plz help me?

Hi..., Can you explain what make/model of device you are attempting to get this code to work on. There is no standardized backlight control API, meaning that different OEMs, may have implemented this functionality in slightly different manors.

Some devices (Symbol and Intermec come to mind) will have additional SDKs which include backlight control APIs which are specific to their devices. The approach you seem to be attempting to use is described on MSDN here Enabling a Backlight in relation to the sample backlight control panel applet included within Platform Builder. Platform Builder is a tool OEMs use to generate the OS image that runs on your PDA and it includes numerous samples which may or may not be utilized by OEMs as they start building their device. It is possible your device does not utilize the approach used in the sample, in favor of an OEM created replacement, due to hardware specifics of your particular device and/or their desire for enhanced functionality etc.

You may be able to find a solution by searching for "backlight" + "<name of your device>" etc, as I'm sure someone has probably attempted to do the same thing at some stage in the past.