For those getting no response at all read below:
Looking through pages and pages of fantastic documentation and i basically had the same issue with my harmony 700 remote, no response no matter what setting i selected. It turned out to be that I had debugging turned ON for the USB device on the AFTV. That pretty much disables the USB port on your AFTV device.
I'm still getting the occasional repeats (up/down) but that's manageable for me.