How to specify specific folder for all Pages backup files

How do I get Pages (or some clever Applescript???) to ensure that all Pages backup files are stored in the same place (ideally a folder on Dropbox). That way I can ensure that I have the magic third backup of important files (Timemachine/CarbonCopy Cloner are the two seperate hard drive backups).

Doesn't seem to be a way of doing this in preferences (I am using Leopard btw not Lion)

Thanks clever people ...