The original MB is IBM BARBADOS FRU 39J6196. It has a connector for a front cable cable labeled AIOFP. The <B stopped working so I replaced it with an Intel D915GMHLK MB. But (of course) the connection to the front panel are different so I need to modify the cable and replace the single IBM connector with 3 different connectors (power/LED, USB and audio). This is why I need the pin out of the front cable connector.
Ok, Im assuming that the connector from the front panel is just a single block at the minute?
If you have the user manual for the new mobo it should have a diagram showing the functions of each pin in the front panel socket, that will identify which pin is power,ground led light etc,
you may be as well buying a new power switch and just hooking that up, the leds for power/hdd imo are useless anyway I dont connect those myself but to separate the original wires, just follow them from the pwr switch button and see where in the block they go in, but that will only identify where they went on the old mobo.
Hope this helps a bit.