Parking sensor dings with aftermarket stereo
 

Hi guys I have a 2008 535d I have put in a aftermarket stereo but to keep the idrive I just have the power going to the mask unit I have tryed to just wire 1 speaker up to the mask unit, drivers side for parking sensor tones but can't seem to get it to work.
Is there any pins in the plug on the mask that I could just run a separate speaker to?

I have this link but not sure which would do just warning dongs and parking tones
http://pinoutguide.com/Car-Stereo-Audi-BMW/bmw_bussines_cd53_pinout.shtml

I think e60 parking sensor works on every channel. Rear Left speaker, works for rear left parking sensor. Front right speaker, works for front right parking sensor. There are 4 speaker output to connect to rca input new head unit. And how you connect speaker cable to your new head unit? Using high to low converter? That problem make me think twice to upgrade my audio system.

Ah right I see no wonder only me connecting it to drivers speaker didn't work, I know you can get a connect2 adaptor but it doesn't keep the I drive just the aftermarket stereo with parking sensor tones and bongs.