First of all you need a free Primary Partition. For ZFS installation run "zfsinstall" script as root. For example, if you have Solaris partition on c1d0s0, run this command to install MilaX with zfs-boot:
(root@milax)# zfsinstall c1d0s0
If you’ll see an error messages when the amd64 boot_archive created, do not worry about it.
Sample result:

Some notes:
1. The script can only handle already sliced disks (fdisk must be done for the disk before calling the script).
2. You need at least 256 MB RAM for ZFS-installation.

Any additions and changes are accepted.