No dice for me. After following the steps I probably pressed the channel up button 50 times but it never powers down the receiver. There is nothing special about the receiver. It uses regular IR codes. Its just a high end brand.
imahawki, check the product manual that came with your receiver to see if there are any codes listed there for use with universal remotes. The Cox remote should be able to find a code that will at least turn off the receiver. Even if it is not the specific code for the device. Also, you can check with the manufacturer for other codes.
There are no codes in the manual and the steps you linked to above do not ever result in the receiver being turned off so I'm at a loss.
I called Anthem and they told me that COX would have to have the remote programmed on their end. Its nothing that they can control at all because the remote manufacturer has to program the remote with the right code and the 5 digit codes you enter are arbitrary and set by the manufacturer of the remote to denote certain brands.
They list the hex codes for professional custom installers type of remotes. These codes are dozens of characters long for each and every command. They're not like the 5 digit codes COX uses to tell the remote what brand you have.