Blue Amp control wire - connect to HU, Amp _and_ Maestro? [SOLVED]

I'm finally installing my HU. I know the Amp has a remote turn-on wire, it's red at the amp but my kit came with a long blue wire.

Where should it go? The Maestro RR wiring diagram only shows that the blue wire between the T03 harness and the HU should be connected together.

Should the Amp version of this wire T off from that connection, or should be some ignition-controlled wire from the vehicle itself?

Thanks

 

Well I did a T off the blue/white wire between the HU and Maestro