Another GW500 install problem - Help, please!

I'm sorry to start another thread on this topic, but most of the other ones are older and I'm not sure if many people are still reading them, and I wasn't sure which one to add on to, so I decided to start my own. First of all, thank Skylaw and Rob so much for all the contributions they've made to the site, I have used many of them extensively with my work on my new baby, a 2006 S430 4matic. I spend 1.5 hrs a day commuting (the joys of Northern NJ/NY,) so I've been upgrading my car for the ride. I've installed the MB BT module for my phone, which works fine now that it's been version coded by the dealer, but I've been unable to make the Gateway 500 (v3 I believe) work. I've followed Skylaw's instructions closely (I did run the aux input/control cable on the passenger side -- fit better) and have done the switch of the F/O ring in the trunk (I have the phone module, but NOT the Sat radio.) When I reset the F/O ring two or three times, I still get 'System Unavailable' and the Command shuts down. I used the Installation Type 1 instructions from the Gateway Install Guide and have the DIP switches 1-5 off and 6 On per Skylaw's and other's suggestions (I've also tried all off as well.) I've checked the connections multiple times and I know that the GW500 is working b/c the iPod connects to it and I get the logo, but I am at a bit of an impasse as to what to do next. I actually did much of the install several months ago, but wanted to wait to get the MB BT unit installed and version coded before proceeding with the F/O ring change. I wonder if the guys at the dealer did something so that the system would ignore the GW500, as it was in the ring when they version coded the phone (in the original configuration.) I'm hoping it's not that as I don't want to visit them again, as it's always expensive (seem to find something new to fix every time) and they are not that knowledgeable with these types of upgrades. Thanks again for any help or advice you can offer.
Sincerely,
Klondike