在UAC下，为什么我不能将文件写为模拟用户？

I'm impersonating a user until Windows 2008 with UAC enabled. I'm trying to write some files to a temp directory. But even if a user has write access to a directory, when I impersonate that user, I'm unable to write to that directory (I get an Access Denied error). Apparently, this is due to UAC blocking me.I'm impersonating a user until Windows 2008 wit