It doesn't have an extra button. The play button is outside of the circle, instead of inside.

Same codes.

p.

I have to take this one up again.

Now I have got myself an Apple TV2 with the alu remote, and the middle button and the play/pause button has two different functions. 

On the Apple TV if you press the middle button on a movie you get to se some info and can from there choose to play the movie using the middle button to press play on screen.

If you instead use the play/pause button on the Apple remote the movie will start playing imediatly.

Using the BEO4 via my BV8 with PUC codes the go button and tha stop button will do the same as the middle button on the apple alu remote.

I Wonder if B&O has updated the PUC codes so the play/pause button on the Apple alu remote can be emulated?   

There might be another possible option for you. I have a first generation Apple TV. It had a remote learning function. It was able to learn commands from the PUC for another device. 

I know have my Beo 5 programmed to perform the following functions with Apple TV:

play    pause    stop    rewind   fast forward    previous      next track     skip back    skip forward.

Samsung T351