lammert - 3:19 am on Apr 1, 2011 (gmt 0)

Power and sleep buttons are managed by the hardware/BIOS and they are controlled from the operating system over an API. The available functionality may therefore differ dependent on the type and configuration of the BIOS of your computer. You may want to check your hardware manual or BIOS settings to see if anything can be done there by circumventing the operating system entirely.