Music + Charging + Screen Off

[makryger]

So I was trying to use my imagio as a white noise machine last night... I wanted the player to play the mp3 of noise, the phone to be charging, and the screen to be off. But even with the power setting to turn screen off on external power, the screen wouldn't turn off. And if I tried to turn it off myself using the red button, it would turn the music off.

Can anyone else get the combination of music + charge + screen off working?