One could get the function back by using an after market unit. NZ Link make one, and as much as people say about them, you could setup something pretty fancy.
Use the 5 LEDs of the KnockLink as inputs to a Haltech. Switch maps maybe, even flick a mosfet and make the AFM see 5v (to over fuel it)
Just noticed they make an amp called a Knockblock One could use the 0-5v signal again, to input into a stand alone ECU, or use it to fool a Trust, PFC etc.