Emergency Drain fuel tank on SAAB 900

I need to drain the petrol tank of a saab 900 (it has been filled with diesel) tried with a hose but unable to as there seems to be something stopping the hose from getting to the tank.

Is there a another way to drain the tank. Some sort of valve on the tank etc.

Have looked briefly under the car but cannot see anything of that type.

Solutions greatfully accepted.