[Freeswitch-users] Allowing calls with Mod nibblebill and zero balances

I’ve got nibblebill working quite well and it’s a great little mod. However one use case I can’t get to work is allowing calls to happen when a users balance is 0 and I’d like to allow calls if they are ‘internal’ i.e. not using a gateway. Although I set nibble_rate=0, the dial plan doesn’t even get there as it sees a 0 balance and hits the hangup extension. Has anybody this use case working?