API for Asus 1005pe control backlight programmably?

I'm u开发者_JAVA技巧sing VS2008, my OS is Win7. I tried WinAPI IOCTL_VIDEO_QUERY_SUPPORTED_BRIGHTNESS on my netbook. I can retrive a correct the LCD handle, but DeviceIoControl returns 0. I haven't found any APIs for GMA 3150 either.

small example: http://davidxl.blogspot.com/2010/07/controla-el-nivel-de-backlight-de-una.html