For better or worse .....
For better or worse I received the Motorola Vehicle Navigation Dock from amazon.com yesterday (Saturday). The "instruction" manual that came with it was almost useless - three pages (in English) measuring about 3"x4" in what appears to be 6-point type. Bah Humbug! Had to figure out most of it on my own.
Apparently, since I'm not using a rubber sleeve around the edges of the phone, there is a little plastic thingee that acts as a spacer to make the D4 fit very nicely into the cradle. Even without the power cable plugged in, when you install the phone in the cradle you get a menu "VEHICLE HOME" with four options: Navigation, Calling, Voice Search, and Music. This must be a "Smart Action" that is a built-in default -- it was not on the Smart Actions menu.
The device came equipped with a USB to micro-USB cable; the full-size USB cable end had a short (3") pigtail that will interface with your car radio's aux input (if you have one) -- a 3.5mm - 3.5mm patch cable is provided to complete the hookup; alas, my old Toyota Matrix's radio has no aux input.
The actual auto cigarette lighter power plug has two USB sockets. The power plug from the Dock fits into either. I could not tell the difference, so I assume they are both the same, and would like to be advised if one should be used and the other should not be used.
I'm about to take it out to the car for a test drive. Wish me luck!