The manual does indicate upmixing to 7.1 so it's not too old an avr. Good idea on the surrounds as far as avr speaker/channel setup goes, but since his signature differentiated between 5.1 and rear surrounds to come I expected that these new speakers are actual rear surrounds, but good to check....
ps I did reread the signature and think this is the issue since he didn't have surrounds listed, he might have added these speakers as rear surround in the setup instead of just surrounds; many units will ignore rear surrounds if no surrounds are present.