Remember pallet attributes in objectstorage

[depuits]

Currently pallets will forget all attributes related to the mod when placed in object storage. So far I was able to look in the PlaceableObjectStorage specialization in which I've found that the serialization happens by a lookup to ABSTRACT_OBJECTS_BY_CLASS_NAME. But here I am unable to find the implementation of these abstract classes and where they get the properties to save.

local abstractObjectClass = PlaceableObjectStorage.ABSTRACT_OBJECTS_BY_CLASS_NAME[ClassUtil.getClassNameByObject(object)]
    if abstractObjectClass ~= nil then
        local abstractObject = abstractObjectClass.new()
        abstractObject:addToStorage(self, object, loadedFromSavegame)
        self:addAbstactObjectToObjectStorage(abstractObject)
    end

I was able to implement this for bales using saveBaleAttributesToXMLFile but I don't know if something similar exists for the vehicles.