Longhaullincoln

Hello all! 2011 Navigator w THX Audio I have had an aftermarket radio (Boss BE9ACP) installed in my wife’s Navigator for about two years now. It’s cheap, but we just wanted to get android CarPlay functionality first and foremost. Well, we now have kids that listen to music, and when I tried to fade the music to the rear, I realized there was no fade control. I recently plugged in the old unit and fade control does come back. I called crutchfield and they said my only option was a better unit that could pair with an iDatalink Maestro. I quite miffed by this as there is a specific option I clicked verifying my car had the THX sound system. But the tech on the phone said that the lack of fade control is “intended”. My ask to the group is to ask if there is any manual workaround via manipulating the harness to regain fade control. I found some threads a various forums that pertain to the THX audio system, but nothing concerning fade control. Thanks in advance and hope some of you know what the heck I’ll need before I buy a whole new system outright!