Switch to external display without sleep in MBP

Hi,
is there a way to switch to external LCD monitor in MBP without putting the system into sleep and waking it with lid closed using external keyboard or mouse?

I need to switch from internal display to external one without closing or stopping my applications. I have a method to connect external display and set internal display brightness to lowest value (so laptop screen is completely dark), but it's not very convenient way.

It's easily done with windows (I need to use it on my MBP) in display settings, but I couldn't figure out how to do it in MacOSX...

Thanks in advance for help

 

Unfortunately it doesn't work. InsomniaX is mainly for disabling sleep mode when closing the lid.

There is an option "sleep display", but it turns off both internal and external displays. I need to turn off only the build-in display then external display is connected...