The next easiest way, besides what you are doing. Is to press and hold one of the lower hard buttons that says "NO IR" when you bring up (or down) the device menu.

Other than that. You would have to go into TSS, which you can down load from this web site. And delete the action in each of the device menus.

Or you can delete the command on the remote itself. I know what the procedure is for at Pronto, but for Marantz, it should be the same. But I do not know how to get to the set up menu if it's different from the Prontos.

Rob