hfs-3 to aem ems in 02 wrx

[02subysti]

I have the hfs-3 system and im currently in the process of installing. I have an 02 wrx with the AEM EMS system in it. I currently have the fail safe hooked up to wastegate with the brown and white wires but I want to be able to turn the gauge on and it automatically switch maps. Ive heard things about the orange wire being a map switching wire but im not sure which wire to tap into with the aem ems. Any help would be great!! Thanks!!