Managed to get FreeNAS 8.04 to push Rsync to QNAP TS219P11.
I had created a FreeNAS user account and mistakenly presumed that the FreeNAS box would supply the password for that account to the QNAP Rsync server.
It turns out however that FreeNAS 8.04 has no option in the GUI to specify a password for the Rsync user. https://support.freenas.org/ticket/395
Now, there is a workaround. You can use SSH tools to create a file on the FreeNAS box containing the Rsysnc user password and refrence the file from the Rsync GUI. The following two links describe how:http://forums.freenas.org/archive/index.php/t-5025.htmlhttp://forums.freenas.org/archive/index.php/t-5505.html
Also, here are Rsysnc docs:http://www.samba.org/ftp/rsync/rsync.html
I din't use the workaround above. Since I only want to use Rsync to do a one time sync I figured I would try setting the Rsync user on the QNAP device with a blank password. The QNAP device won't let you enter a blank password so I just hit the space bar once for the password which I belive effectively creates a blank password. After that Rsync worked for me.
Hope this helps someone.