OK, another blog post to remind myself -- and maybe somebody else, who knows? -- of how I finally did it.
Yes, from time to time I install other Unix OS's just in order to stay plugged in. The last FreeBSD 9.1 on ZFS was installed to double boot with my current Fedora 18 installation. GRUB2 boots both, it's become really universal now, and this allows to get more familiar with ZFS and its advantages -- which are quite impressing. Especially so after having deleted a couple of times...