Can I encrypt a whole pool with ZFSoL 0.8.1?

I have compiled ZFS 0.8.1 for my server, and it is running fine. I am also able to create encrypted filesystems like mypool/myencfs.

However, mypool is also a filesystem, and it seems that I cannot enable encyption on it:

zfs set encryption=on mypool cannot set property for 'mypool': 'encryption' is readonly 

The pool is to be decrypted with a keyfile from another encrypted drive, so I would like to put the inheritable properties as high as possible, an also not risk unencypted data when I accidentally copy something to mypool/