[Antidogma]

Hello:
The other day I had installed an aftermarket head unit to replace the Top HiFi OEM Alpine radio on my 2008 328i (E90).
After reading several posts, I had the OEM head unit relocated to the trunk, and I had several wires run to it, including the High and Low CAN bus.
I then had an additional speaker installed in the empty center channel to take care of the chimes warning for opening the door while ignition key is in, parking brakes and seat belts.
My car is also equipped with rear parking sensors, that I thought go through a different loop. However, I have now realized that I lost the parking sensor beep.
Maybe is something as simple as having to reprogram the car, but I am afraid to have lost them for good.
Does anybody on this clever forum has any info, feedback, suggestion? Thank you.