How to autostart/boot laptop when AC connected?

Inspiron 6400 with WinXP. I have set the power management to do an immediate shutdown with removal of AC. I would then like the system to autostart/bootup when AC is restored. Desktop systems have this setting via BIOS but laptops do not seem to have it. Also, I thought about using USB wakeup but since AC will be removed, the USB ports go dead. Not sure there is anything possible with Wake On Lan which I do not see in the BIOS for this system. Any ideas would be appreciated. I have been researching this for some time. Thx for the help!