the nav instructions say it can be done. Just like you I received only some stupid operating instructions for the DVD headrests. Sorry to have misinformed you about the instructions.
The reason i assume it can is because the dvds have an AUX function. I could be wrong. I an still trying to contact Invison and figure it out.
There are installation instructions at this site:
http://www.invisionindustries.com/rev_instructions.html
These are vehicle specific, none for the H3. But you get the idea of the install from them. They dont have any technical stuff though, just how to install it.
Also next time i go to my dealer (probably within the next week or so) i will ask them to make me a copy if possible of any instructions they may have. Will post those when and if i get them.
I think i found the connector type from those links you listed. Will try and find some tommorow to check if they are the actual ones. Will post the type tomorow if they fit.
Hope this help, and thanks for those links again, saved me lots of time!