Can't do it like the Brits have with Egypt and Canada?
Or make North Africa (or one city) a sorta independent colony like with your extra country spot and there you go.
Better than having all those British and French subs just sitting on the Norway route. Nice touch, but you need to spread them out.
Now, if you could link a successful sub raid to the Malta Effect, that might be cool too. Although, leaving it out would give the Allied player an incentive to move a Bomber down there to close the ports on either end.