This is not a problem. This is the feature
If you have the GS7 then you can call the SHGetFolderPath function (contained in the shell32.dll version 5.0 or later) using liteC language, save returned path string, concatenate it with you file name and do what you need. If you're using older GS version then you can build "wrapper" dll for some needed OS/shell interfaces to call the wrapper from C-script. That's all...