Looking to install an after market DVD headrests in a 2010 EB with Nav. Most that I see only connect to the speaker sound systems via FM transmitter.

My Nav screen has controls for a DVD player and I am wondering how do i connect an after market player to the stock Nav system to get direct audio feed into the system AND to use those controls? Is there a wiring harness I can get?

I really don't want to go the FM Transmitter route

Thanks