To answer my own question - apparently IB can't do it any more due to new reg's, but buying the ASX USD ETF may be the way to go I'm told.
AN1 CuFe sells its Crossroads gold royalty to Northern Star for $4M cash; says better than waiting for mine launch
Week 46 Wrap: Copper hits 2mth low as Trump threatens net zero pace; US rally fades; HotCopper’s picks