Have you tried calling their tech line? Last summer I called just to ask some questions and found them to be a very friendly and willing to support their product. Or if a search of this site does not turn up anything try
www.w116.org.
Some people have had good luck with the factory manuals on CD, tho I prefer to take a manual to the car.
Please keep us posted as there are quite a few of us W116SD owners out here that would love to upgrade to the Unwired system.
Good luck and look forward to hearing of your progress