Hi Noel,
had the really same prob with the AVR 5000, first with the Neo, then with the Marantz 3200. Had lots of fun with the remotes, so i bought the Marantz 9200. That is able to learn the buttons of AVR!!
I copied the hex-code from the 9200 to the 3200 and it works, have just done it for DVD, but works for the other for sure... When you are able to work with the hex-codes, i would e-mail the codes you need.
I found before the codes in the files area, but they did not work, i think because we have a european AVR 5000!?? Let me know if you need the codes,
Oliver