i tried the same procedure as you did and had no success at all.. it seems that zune v3 installer will update the ibx to the newer version. in the past (while zune 2 was the last version) i used to strip the drm with
freeme2, but after the zune 3 came out, i wasn't able to strip anything since the keys were updated as well.
it seems M$ won since zune 3 came..