Jack that is my method aswell but i put 2 peices of wood either side of the cam in the vice so i don't knacker it up and then use stilsons and brute force (smells nice) and unwind the variator from the cam.
Just ensure you put on thread lock when you put it back on !!!
P.s don't forget those cam locks as it is hard todo without
i viced the camshaft on the the closest cams to the variator, using a sheet of brass to protect the cam, machined 2 pieces of steel rod to fit tight in the largest holes in the variator and tried to force with a bar, but too tight....so heated the variator with the gas and it went.and my hand went red when i decided it must've cooled down enough to pick up 5 mins later!doh!