Trade Cart Attack Reaction

A scenario I am working on requires Trade Carts to not flee when they are attacked while in motion. That is, by default trade carts will flee from attacks much like villagers but I want them to behave like regular units and continue onward unabated when attacked.

In AGE there is an obsolete variable for Attack Reaction that appears to have done what I needed; however, as expected this variable no longer does anything.

Is there another variable that I can modify that will have the same effect?