my way works and sucks too: i cheat a bit to install zeroshell on my hard disk:
i copied the zs.usb.img.gz image on an usb card with ext2 filesystem
then i boot the live cd
# mkdir /mnt/usb1
# mount /dev/sdb1 /mnt/usb1 (where sdb1 device is my usb)
# gunzip -c /mnt/usb1/Z*.img.gz > /dev/sda (where sda is the hard disk)
then rebbot without the livecd, and it should work, it should boot without the livecd.
far away, it is possible to modify the initrd to customize ZS, at this point, the root system files are still loaded in ramdisk. sorry for my poor english.
Joel MBA OYONE.