I also needed a front panel switch for power and the only way to do this was to solder 2 wires onto the pads of the existing switch on the board. There is no external power connection for the T4. This is something FA should consider for all future boards as once installed into an enclosure, the board mounted power button is not available.
My T4 is mounted 50mm on standoffs and I put a Molex KK 2 pin connector on the motherboard for this to plug into. A ribbon cable connects the GPIO to the motherboard.