From readme.txt in scripts344.zip:
JFW_Attach_Script_Vehicle_Created (attaches a script to all objects vehicles when they are created)
Script (script to attach)
Params (parameters to use)
Delim (delimiter, anytime you see this in the "params" string it will be replaced with a comma)
Player_Type (what player type to attach to, 0 = Nod, 1 = GDI, 2 = any)
Note that all the _Created scripts won't trigger for objects that are placed on the map at startup, only for those created by the game
This includes the players, vehicles they buy, harvesters etc but not preplaced things like the building controlers.
Although there are a few instances where the Object Create Hook might not trip (e.g. certain spawner objects). This is because those objects don't
call through to ScriptableGameObj::Start_Observers (the place where the scripts get started up and the place I am hooking)