Hi
not exactly the answer your looking for but here is what I have done
I have a 1000 WATT inverted hardwired to my battery with a universal power cable running to my laptop. i leave my laptop on standby so when I touch my wireless keyboard or touch the screen it soft boots into windows and when i want to shut it down i just put the laptop back into standby - this my cheap and VERY effetive startup shudown controler :P
hope this gives you a few ideas.
oh and i have the universal power supply so i can leave my good HP one in the laptop case at home for when i use it as a normal laptop like yourself.
If you would like some help or pictures i would be hapy t email so please email me at
jamie.whittingham@gmail.com
cheers
Jamie aka Quest