Heliduck,
As far as I am aware you can't hook straight into that. Last time I looked it up it said that you have to have 40hrs of Air attack on fires to fly the bucket, and mustering ag and low level wont do. I also think you need a 100hrs on type to fight fires and a bucket endorsement with some duel fire training.....but this was a while ago i looked up those regs. You will find the government are the controlling hand it the specific requirements in regards to fires...