That pulley does come off the hub. I think that I have a photo somewhere, but I know that it is really hard. It was assembled with Loctite thread locker.
That's why, and when you have the pulley on the floor it is hard to hold it still while getting the torque on the bolts. An impactor (as mentioned) would be good, or maybe a little heat from a torch, too, but I fought them off the hard way.
I took mine apart to paint it. The inside rim on the pulley unbolts too...much more easily.
Maybe if the wheel is on the bike it would be easier to break them loose first and then remove it for the rest.