Just installed a USB cable on my iMiev - found a cable in Ebay for $3.15.http://www.ebay.com/itm/USB-Cable-Audio ... 2301587984
After popping off the radio bezel as described in links earlier in this thread, I looked down at the radio and realized I could get my hand in there, barely; could reach in and feel the socket where the cable goes (on the left side of the back of the radio), and also feel grooves at the top of the socket - meaning the grooved end of the cable needs to face upward. I was able to plug this end of the USB cable into the radio without much further ado, altho it's a tight space and I don't have small hands.
Looking down at the radio, I had noticed there were gaps going all the way down under the dash. I also found it's possible to reach behind where the USB panel plate is mounted, and just pop it out. So I snaked the USB cable down, cut a rectangle in the panel plate (the most difficult part of this venture), and glued the USB cable end in place with "Goop."