I use hdmi screen with closed rmbp. I used to have mirroring only so when I opened the lid it did the settings by itself. But now when I open I use them sometimes for dual screens for designing stuff at home. I did get a smal bug at start that made it hard to configure the screen size thou. Might be gfx failure.
In bootcamp win7, when I closed the lid it put it into sleep mode but never came back on for some reason so I just turned that off and set the rmbp screen to never turn on.