Reduce “BACKLIGHT” brightness in windows Embedded standard 7 using vc++

[san500052]

Is it possible to reduce the "Backlight brightness" in Windows Embedded standard 7, Monitor:Samsung DE40A programmatically with vc++ ? It is possible to reduce monitor backlight brightness with the monitor's remote.

I have been able to reduce brightness,contrast,gamma, and RGB values with the respective APIs SetMonitorBrightness, SetMonitorContrast, etc. Tried to use DeviceIoControl function with IOCTL_VIDEO_QUERY_SUPPORTED_BRIGHTNESS but the function call doesn't succeed, it gives a non-zero value and according to msdn the function has failed.
//Get the handle
HANDLE hLCD = CreateFile("\\\\.\\LCD", // open LCD device
GENERIC_READ, // access to the drive
FILE_SHARE_READ|FILE_SHARE_WRITE,// share mode
NULL, // default security attributes
OPEN_EXISTING, // disposition
0, // file attributes
NULL);

if (hLCD == INVALID_HANDLE_VALUE)
{
cout << "error: Invalid Handle, unable to get LCD handle" << GetLastError() << endl;
return 1;
}

BYTE SupportedBrightness[256];
DWORD nBytesReturned;

int nRes = DeviceIoControl(
(HANDLE) hLCD, // handle to device
IOCTL_VIDEO_QUERY_SUPPORTED_BRIGHTNESS, // dwIoControlCode
NULL, // lpInBuffer
0, // nInBufferSize
(LPVOID) SupportedBrightness, // output buffer
sizeof(SupportedBrightness), // size of output buffer
(LPDWORD) &nBytesReturned, // bytes returned
NULL // OVERLAPPED
);

if (nRes == 0)
{
cout << "error: Backlight Not Supported" << GetLastError() << endl;
return 2;
}

cout << "Supported levels:: ";
for (DWORD i=0; i<nBytesReturned; i++)
{
cout << (DWORD)SupportedBrightness[i] << ", ";
}
cout << endl << endl;



I end up getting "Backlight not supported", but I can change back light brightness from Samsung Monitor's remote.
Please suggest any known method to reduce back-light brightness programmatically.