unfortunatly in Australia the cyclinders are all owned by the gas companies and they wont fill an un-certified cyclinder. They will not certify privatly owned cyclinders, so they have you by the nuts.

You MUST hire a cyclinder from them if you want gas.
Yes its a con, but thats they way it is.

The big difference between the BBQ gas cyclinders that we can own here and the MIG gas cyclinders is that they are used in industrial enviroments where the OHS legislation is very different.