You would need the IR codes from the Microsoft IR keyboard that they used to sell, plus your PC would need an IR receiver (which I'm assuming it already has?)

I'm surprised CCP doesn't have the IR codes for the keyboard, it's been fairly complete from what I've seen so far. I know Logitech has the codes for the keyboard. That said, I'm not sure how it handles double-key presses like Alt+tab, unless there is one burst for keydown and another for keyup, so it might look for "alt keydown, tab keydown, tab keyup, alt keyup" to know that a key combo was pressed.

If you can't find them somewhere, I own one of the keyboards and could try to learn it for you...