I have 2 RC64RB's and both work just fine with all of my HR2X's, not sure why they'd tell you they won't. Is your HR20 setup for RF or IR? If you're setup for RF you'll need to set it to IR for it to work with another remote now.
You can do that, and access your recordings, using the buttons on the front of the unit. You can press "Menu", left side center button, and then use the arrows around the LED ring to move around the menus. The button in the middle of the light right is select. You just can't do any trickplay with the front buttons. And there is no stop button on the front either.