2013 Prius C Two - No Backup Camera Harness? Help!

Hi all,

Recently got a great deal on a 2013 Prius C two from a friend. One of my first orders of business was to upgrade the crappy stock headunit to the upgraded navigation unit for XM radio and a Backup Camera. I got the HU out of a junkyard, it's all installed, works great with XM and GPS....however....when I went to install the backup camera kit found here -

- I couldn't find the pass through harness to attach to the back of the HU.

I've done a THOROUGH search of the forum and can't find an answer in any of the similar Nav upgrade guides. Has anyone got this working? If so, all help is appreciated!