Business Application Rules - Times allowed to be active

I am using a Business Application Rule Non HTTP to route from the WAN to DMZ VPN ports. All works lovely, except of course the 'foreign naughty people that seem to love testing my security at night. Is there any way I can automatically turn these rules on and off like the User Network Rules? The VPN will never be used over night anyway, just cannot think how to do this?

thanks in advance