That's the adaptor I had my eye on, however when I spoke to connects2 to confirm compatibility with both steering wheel controls, and reverse sensors, they came back with the suggestion of the
CTSCT008 -https://connects2.com/Product/ProductItem/CTSCT008
I'm using it with a Sony (and the multi lead remote cable), with very good results, however there are a couple of caveats...
The steering wheel clock controls are a little bit funky. They basically work quite well for most functions on the clock display, and flawlessly with my headunit, providing you read the instructions. It may depend on which version of display you have. I have the older, more simple (type A?) display. Sometimes moving between the page where you set Year/Month/Day/12-24/AM/PM doesn't seem to work. I'm not sure which combination of presses makes it behave, but I had to jump in and out of that page a few times before the scroll wheel would move between those options. Got there eventually, but you might need some patience. (...and jump leads at the ready if you play for too long - don't ask me how I know, but one thing I will say, with an aftermarket radio, economy mode doesn't save you any more!)
The reversing sensor tones - When I spoke to Connects2, they couldn't categorically confirm the
CTSCT008 would work with all variants of parking sensors used in Berlingos. They asked if my tones were usually generated at the rear speakers (which they were with my factory non-bluetooth, aux in the glove box version of the RD4 radio) If your tones are in the rear speaker, this seems to be a good indicator that it will work for you. The other parking sensor variant is apparently less common. My B9 is a 2009 built model. I took the plunge and bought the adaptor after reading another thread on here about using a Lexia to divert the tones to a speaker in the steering column, which would have been my plan B if it didn't work out of the box.
I'm not sure if the tone is generated by the aftermarket radio, or the connects2 box, but the tone I have now is a bit harsher sounding that the factory beep. Not a biggie, just something to note. The seatbelt warning tone was unaffected, and seems to originate from the aforementioned steering column speaker.
Hope this helps - give me a shout if you have any more questions.