I opened up my D600 front and I looked into the connections of the power button. I found out that I needed to short circuit pin 1 and whichever of 2-6, that doesn't matter. As long as pin 1 is connected to another the laptop boots. I'm researching the soldering option.
Now I looked through the P2140 but since I'm just starting I couldn't figure out if that has a automatic starting cable that connects the two wires. Does the ACPI connect the two wires or how do I proceed from that? I want those two wires to go into the P2140 so that I can get rid of a starter button, I want that to boot automatically.
The Wake On Ring option doesn't work since the BIOS is seriously handicapped and for the WOL option I haven't found a usefull tool yet. USB won't bring it out of hibernation and I don't want to run the risk of draining the car battery if I use standby.