Have you guys tried just teaching the remote the buttons (Learning code 975) WITHOUT bothering with the device codes?
I have the old 1056B01 Atlas remote (no backlight), and it seems I can teach it in any mode from any old remote I got. My AUX device code is 1972 (XBOX 360, under Microsoft VCR or PVR in the guide), but I can shove an LG TV remote's Sleep button in there on the triangular A button, my Samsung DVD/VCR remote's Power button in there on the square B button, and my Motorola Cable Box remote's GUIDE button (from my back-up 1056B01 remote) in there on the circular C button. In AUX mode, it sends signals understood by each of 4 machines.
You can disregard the codes completely. The remote has a big database of presets for the button signals used by various machines of many popular brands, in which a single preset is looked up by the device code, but if the codes in the guide don't work, and the search turns up nothing, it just means the machine you are trying to control either came out after this database, or for some reason, it didn't get a button preset developed for it. Even then, there is a good chance the remote can learn the individual button signals anyway.
You can disregard the device types too. My AUD device code is factory preset to 1023 (under RCA Audio Amp/Tuner), and I can put in whatever TV or VCR or Cable Box functions I want on any of the programmable buttons. Each device code seems to uniquely identify what device type it is for, merely by referring to a button preset that is for an audio device, or a TV, or whatever it is for. Putting the same code for several device keys works okay, regardless of what device type goes on what button. The device type for the key, which you reassign with code 992 (turn the DVD device key into a TV device key, for example), only seems to be used during the code search (code 991) because the remote tries a sequence of different codes for the type of the currently selected device key only.
The point is, you can program the remote (1056B01, NOT the inferior backlit 1056B03) without the device code, even if the code search turns up empty, and without worrying about the device type (AUX, DVD, AUD, TV, and CBL). Without using the device code, I don't think you can actually get the Power button working, since you can't directly learn on the Power button, so you have to put the Power button on another Atlas remote button. The Power button is not an exception to learnable buttons in the instructions, but it doesn't seem to accept learning.