Ok here's a rough description of where point P leads to on the pinheaders. Look at the top of your mobo, with the video cable adaptor facing away from you, and the controller ports facing you. (i know you have your mobo in hand w/o the case, but visualize this for me). Look at where the yellow bundle of cables from the FRONT POWER AND EJECT BUTTONS (there are like 10 wires) connect to your mobo. It's similar to how your controller ports connect to your xbox, but this is a large yellow bundle of wires. the point P corresponds to the lower left hand corner pin. test that point, it should be point P. Just solder a jumper to this
If this doesn't quite answer your question, i'll try to phrase it a different way
Kyle