Need help converting the backup camera from a 2012 mirror plug to a 2014 head-unit

Two years ago I added a 2014 tacoma stereo to my 2012, with all of the proper wiring and conversions. My truck never had a backup camera but was wired for one, and now I want to add the camera to my tailgate since the wiring is mostly all there. My problem is now figuring out how to get a connection from the existing harness (sitting in my headliner above sunglass slots) to the 2014 stereo. The connections are different, I have a 14-pin male plug from the truck, and a 24-pin female plug behind the stereo. If anyone has done something like this or knows of a thread that explains the fix, I'd greatly appreciate it. I've searched tons of threads now and none mention this exact scenario with a solution. Maybe two separate harnesses that can plug together, or a single harness that makes both connections? After the work I put into this 2014 head-unit to make it work, I'd hate to have to buy a new mirror to see with my camera.

Images:
2014 head-unit (photo from internet). Camera connection is on bottom right- 24 pin
Male 14-pin plug from inside my cab

 

There's another connector, IO1/IO2, before the overhead one I8 (14 positions).

It's attached in front of the cabin fuse box.

Part# 90980-12554 for head unit could be had with pass-through wires and a breakout to this connector.
PM @kmorgan3, he might find time to sell you such custom item.

 

Thank you, this might be exactly what I need. I’ll update with any progress.