Hello,
you're using Windows Vista or 7, I guess. These versions have a keyword feature in themselves. So what you enter in Windows, is stored in your Windows, your hard disk.
The keyword feature of Alfresco is completely separate from that. These keywords cannot be altered via CIFS.
The only way to do it, is follow the link to the Alfresco interface in the CIFS folder and go to the edit page from there.
You could maybe insert a shortcut to that page as a link in CIFS, but I'm not sure, it will work.