06 ML 500 OEM Integration?

Okay so i know Alpine makes the V-hub, i called them up and asked if the v-hub was able to integrate, they told me i needed some type of interface like NavTV or Nav on the go. I called NavTV, they dont have a unit to control the 06 nav yet.

My question is, does anyone know of a place that makes an interface so that i can connect the V-hub to the stock navigation unit. The customer would rather have it this way instead of buying a whole new unit. Also, could someone give me the website or phone number to "Nav on the go"? i cant seem to find it anywhere.

Thanks for all the help!