HOW-TO:Setup All-for-One JP1 remotes
Firstly, this How-To assumes you are already familiar with "JP1" based "One for All" remotes. If not, please go here to learn more: 
To proceed, you should have a compatible JP1 remote, appropriate upgrade cable, and be familiar with using the keymapmaster spreadsheet, and IR.exe. I'm assuming that you already use a JP1 remote for the rest of your AV equipment or you wouldn't want to add your xbox to it! If any of this is not familiar to you, please refer to the link above!
It is important to note at this point, that not all IR remote kits for the Xbox are created equal. This how-to will point you to the upgrade required to work with an OEM Microsoft IR receiver. Other brands use different codes and are therefore not compatible with the upgrade noted here. (You may very well find a compatible upgrade on the hifi-remote site).
You can find the Keymaster upgrade here: 
- Download the upgrade noted above.
- Open the keymapmaster spreadsheet, and load the upgrade. Note that this upgrade is for a model 8910 remote. If you have a different remote, simply change the remote field on the setup tab of the spreadsheet, and then organize the buttons on the button tab of the spreadsheet to meet your needs.
- If you make any changes to the upgrade, be sure to return to the setup tab and save your work.
- On the setup tab, copy the upgrade code.
- Open the IR.exe program and load your remote's programming file (assuming you already have a JP1 remote that has been configured and you wish to retain the rest of the programming when you add this upgrade!)
- On the devices tab in IR.exe, click Add, and paste in the upgrade you copied in step 4.
- return to the general tab, and assign the upgrade (DVD 0522 unless you changed it) to one of the buttons on your remote.
- Save your new remote configuration.
- Download the configuration to the remote.