Oops! I just posted a similar question in a separate thread (and then discovered this thread!)
After a lot of looking around the Web, it seems like a reasonable deal would be to just buy the Microsoft Media Center remote (see NewEgg)
[Link: newegg.com]and simply use it for its IR receiver and pair of blasters.
But I have the question whether the Harmony 880 can "talk" to it. Check out this link for some interesting information:
[Link: byremote.com.au]