I have a Denon receiver with Airplay. Airplay works, mirroring does not: What gives?

I just started using apple products (starting with iPhone 5 for me and the wife) due to the screen's sexiness, my HD music collection, and most importantly because my Denon AV receiver has Airplay built in. I love the Airplay from my iPhone and even for HD tracks I have Airplay support with Golden Ear. But what I really want is a mirroring capability and some more firepower so I got a bottom of the barrel mid-2013 Macbook Pro 13. It has the latest OSX (10.8.?) and it shows the Airplay Mirroring Option in Sys Pref. Here is where I get confused:

Airplay from the MacBook does indeed work with iTunes (although it is slower than the iphone). But, I cannot get the Mirroring menu to even show the Denon as an option. I have this horrible feeling that mirroring only works with Apple TV even with an Airplay equiped device with audio and video processing?!?!?! I truly hope i am wrong especially since Denon is a featured Airplay partner. I am really getting into this whole Apple thing so I really want the mirroring to work since that is 80% of the reason I forked over the cash for the MacBook when i have multiple other working machines (20% was the trackpad). I currently use a linksys N router. Would using the Express router do anything? I have one that I could move over there. I don't see how it would make a difference just brainstorming. Any ideas?

Thanks!!