Hi
To get the driveshaft off the outer CV I would separate the CV from the hub carrier, then I used a soft metal hammer or steel one if you are replacing the CV and clamped the driveshaft in a vice with the CV hanging don. You then have to strike the CV downwards hard. This is to force the round circling on the shaft to compress and allow the shaft to come out of the CV....
Not elegant, but I do not know of another way!
Peter