Thanks for your input on this. I did finally get a reply from Denon:
"Unfortunately, since iTunes is not a music server, there is no streaming from iTunes to the receiver over the network. Apple makes devices that they stream to which can connect to the receiver with an audio cable."
"Unfortunately, since iTunes is not a music server, there is no streaming from iTunes to the receiver over the network. Apple makes devices that they stream to which can connect to the receiver with an audio cable."