Effects can be added by attaching to emitters placed in the model as Clive has done or via X Y Z co-ords. The name of the emitter and the X Y Z position are aircraft specific, you have to use the right emitter name or manually position the effect to the specific location on the aircraft. Orientation can be set either by the orientation of the emitter in the model or by using RotX, RotY and RotZ, if using the XYZ method. However, this is only for effects added to the effects section of the xdp and does not include damage effects. These are added in the systems section and the emitter method is your only means of placing and orienting effects. XYZ will not work as far as I can tell. Certain kinds of effects can have their position changed in the in the effects.xml, which would require a separate effect to be created for each one you want to display on the aircraft but the kind of effect used to make bullet holes and oil or blood splatters does not have this option available, so I'm pretty sure the only means of adding them is by emitters as Clive has done. This means you have to have the source files to add them and there can only be as many as there are emitters created for them in the model. I have periodically tried to find another solution but so far no luck.