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.
Moto