My advice would be not to fuck with anything steel/iron anywhere near the alloy steerer. The PVC pipe is a good trick. You don't need to cap it / hammer it either - just turn the fork upside down and make gravity and momentum do the work by bouncing it a couple of times.
definitely PVC pipe. make sure the business end is a perpendicular to the length of the pipe otherwise it won't get the race on straight; you'll have to bugger it around some to make sure its flush on the crown
So, I finally got around to cutting a few steer tubes. The headset installation/using the star nut as a press technique worked a treat. Easy peasy. A little grease and a three way allen, and it was done.