It works as is (you don't need a plugin really), but it works best if you use the KeyFactory plugin so that you can define your own actions for a bunch of the buttons.
I've been seriously considering writing my own plugin for the RW2, simply so that I could define different commands for those buttons depending on which application is active. Of course, that would take some time (of which I have extremely limited supplies).
Either way, it should work just fine out of the box. To make it better, use the KeyFactory plugin and define your own actions for the buttons using MC's keypresses. I also map functions to the "colored" buttons (on the RW2) that correspond to MC's forward, back, F11 (which cycles full-screen, standard, and theater views), and a special script that takes you right to "Now Playing" (which isn't that hard to set up).
Works splendidly! I just wish I could re-use those buttons for other functions when say, FireFox is the active App.