Standby by pressing Power Button

Hi!
I am a System Manager an i have to configure the power management for about
5000 clients. I can do most of the configuration i need with the powercfg.exe
command.
I also need to configure the "Pressing the power button" on the machine to
enter standby.
Is there another switch of the powercfg.exe to configure that?
Or is there a Registy Key to set that?
Any other way? like wmi?