Hi Nick,
I have got this to work but it's a bit hit and miss to be honest :-/
They way I would do this is before MB is run then copy the rules.ref and config file to the correct local folders.
MB should then see the rules.ref as being up to date and not offer to download them again.
Having said that MB really doesn't work without an Internet connection; it will exit if it doesn't see one so perhaps this is all a waste of time anyway? :-)
Kind Regards
Simon