I have a Harmony H659 and a Denon 3808CI. I am trying to set up the remote to play digital music from a networked computer. Based on what the Denon manual says, I need to use either the NET/DTU or NET/USB buttons on the remote. The setup program for the Harmony does not offer these options either standard, or in the list of remote commands. Anyone know how to set this up?

I have the 680, not the 659. If the 659 has the ability to learn codes like the 680, then just teach it the code for net/usb and add that as a button on your harmony.