Yep it Can be done internal, the second trigger needs to be the avcs feedback sensor on the right bank, and the third trigger is the left avcs feedback sensor, you need to check if rhe feedback sensors are vr og Hall, as there is both kinds, depening on spec.
Then the newer is supposed to work, but i have not had the time to test it yet, but have a engine in the enginestand ready to test on,
But i have other impreza's to work on before , As the engine in the stand is my own, so that is down on the todo list
/Skassa