Factions PVP disabled in enemy territory?

Hello.
I own a factions server and when my players go t raid a faction, and enemy them, they can hit the players in the enemied factions, but they wont take damage, at all But the people inside the base can hit the people who enemied them and they tae damage. I have pvp enabled in factions config file, and pvp is anbled acrosss the server. Players can pvp everywhere else except when it's an enemy faction. Can someone help me figure this out ASAP? My players wan't to raid :3