Yes, you're right, this option is available in the pro-version.
But for backup issues you could use the inbuild backup function (Menu 'Extras'). There you can choose the folder where to put the backup.
Or like I do: usually windows puts the SiDiary files in my german XP into C:\Dokumente und Einstellungen\Joerg\Eigene Dateien\SiDiary\
But I have moved and renamed 'Eigene Dateien' into D:\Arbeit\
Now I have my SiDiary data and config files in D:\Arbeit\SiDiary.
The reason for this: it's much easier to go to this folder and to backup it. And it's not on the same partition like windows itself, so if the windows partition crashes my working files are a liitle bit safer

And here the good news for today:
The Update is online and can be downloadedIn this update you an choose the program folder
or the data folder to migrate your V5 data into V6
