One more idea. I've seen a plumbing tool for gripping the INSIDE of a pipe and turning it (wish I had one when I re-plumbed 14 radiators, I tell you), hex head on a shaft with two slightly-non-concentric knurled cylinders that "jam" against the inside of the pipe for grip. No idea if any of the available sizes match the inside of the freewheel area inboard of the removal-tool area or if there's enough depth to let this tool worth, but I thought I'd toss it out there.