CUDA file does not have scope

I may have a problem on configuration of my CUDA in VS2012. Several Month ago I configured in my old laptop and it succeed. However I changed my computer, it is a x64 machine, I followed previous configuration, and change it accordingly when there is an option for x64(including setting up environment variables, property configuration, etc.). The result is I can run cuda program, but the file does not have a scope like normal C/C++ file, and keywords are not highlighted. So does anyone have experience on configuration CUDA in x64 machines, or can figure out what happened here why cuda file does not have a global scope and keywords are not highlighted in VS2012. Thanks!