Precision 5820 Schematics For Board Hosting Power Button & Intrusion Circuit

Hoping someone has had some experience with integration of a system power management command utilizing the PWR_REMOTE header on the MB, repurposing the Intrusion circuit located on the Front Panel daughterboard, and/or the Power Button adjacent to the Intrusion connector on the daughterboard.  If there are any schematics covering these components that would be helpful as well.  I've been able to uncover bits of information leading me to believe this could achieve the following - Integrating a Koolance EX2-1055 water cooling system, there is a circuit identified as an "ATX Passthrough" designed to be connected to the power button after disconnecting the power button's power wire. A short extension attached to the ATX Passthrough is then inserted into the system's power button wiring that was disconnected in the previous step. 

That was the "perfect world, simplest" method of installation.  Unfortunately, Dell's power button is far more complex. Soldered to the daughterboard, there also the power button appears to have 4 terminals (2 large, 2 smaller) at the rear of the button and soldered to the board.  Given the soldered connections and complex nature of the switch, best to pursue other options.  

That led me to chasing down a suggestion down repurposing the intrusion circuitry. As many know, the Intrusion alarm/switch will shut down the system immediately if the side panel is removed.  When the side panel is removed, the intrusion switch "closes" the circuit, triggering system shutdown.   

So, wiring the ATX Passthrough wire to the intrusion connector's two of three pins on the "inside", or towards the center of the PC is the first step (substituting the connection to the power button).  Note - the intrusion header is 3 pins.  The intrusion switch connector used a jumper to short the two pins on the "outside" (towards what would be the outside of the PC case). Using a male to male single jumper, the two outer pins were shorted.

That leaves the short "pigtail" off the "ATX Passthrough".  There is a header on the MB labeled PWR_REMOTE used for remote power management, system shutdown and restart for example.  It has been suggested use of this header will allow triggering of the shutdown command.  Attaching an extension to the "pigtail" of the ATX Passthrough allows routing of that wire to the opposite side of the case (what would be the left short side of the 5820) where the PWR_REMOTE header is located.  The Owner's Manual warns against attaching the ATX Passthrough to an incorrect  header - very close to the PWR_REMOTE header are two other headers, one being a CMOS reset and clear PSWD.  

The third option is the lease desirable. While it does not require manipulating the intrusion switch and wiring, it adds another PCIe card that complicates things quite a bit. With dual GPUs installed, they take up 4 slots. The first slot is a wifi card, the sixth slot is only a PCI slot, plus the card opening is occupied with coolant hoses.  The lack of slots wold require additional hardware to accommodate a PCIe expansion.

If there's any knowledge, schematics, advice, please do share. It will be appreciated.