rrsync in authorized_keys

Hi all!
I need some help to become better at FreeBSD.
To handle rsync backups to make root be able to sync needed files I usually use:
from="X.X.X.X",command="/usr/share/doc/rsync-3.0.9/support/rrsync -ro /" .....
in my other machines (Linux) in authorized_keys.
I can not figure out the way to do it in FreeBSD.
When I install rsync with pkg, rrsync does not come with it.
What is the FreeBSD way to do this?

Many thanks in advance!
It's not part of the original rsync distribution, therefor it's not included.