[Q] Car Bluetooth with Redmi 1S and Voice via SIM2 topic

I have installed Carbon ROM on my Redmi 1S for a few weeks and have a question regarding bluetooth connection in my car.
I am not sure if this issue is a general problem because i only have tested the phone with Mookee and Carbon ROMs so far.

Here my issue:

In my Redmi 1S i have 2 SIM cards. SIM1 for Data Connection, SIM2 for voice.

I connect the Redmi to my car via bluetooth.
In the display of my car i see the info and phone book from my SIM1.
When i dial out it uses SIM2 as i configured it in the phone settings.

My problem: When somebody calls me (on SIM2) the call is not directed to my car bluetooth. I do not recognize somebody is calling me. This i only see on my phone.
When i take the call on the phone, i can speak via car bluetooth.

Is there any way the the car bluetooth can recognize calls on SIM2?

Thanks for any help!
--cma