Spring 2 + Aspectj, no working when fetching objects from database

[Emili Calonge]

I'm using aspectj to inject my dao into my domain objects, so I can have only a persist method for every domain object and call it from different actions. The thing is that it was working perfectly until I wanted to delete an object.
If I want to create an object I just use:

private Car;
@Action(value="addCar", results=@Result(name="success", type="json"))
public String addCar() throws Exception {
     car.save()
}

and in my Car.class I have:

    
@Autowired
@Resource
private GenericDAOInterface dao;
public void save() throws Exception {
    dao.insert(this);
}

And this works perfecty. The car object attributes are being filled in the form and then I submit to the action. But now I've created my deleteCar method, and it's not working.

    
@Action(value="deleteCar", results=@Result(name="success", type="json"))
public String addCar() throws Exception {
     car = dao.findById(1);
     car.delete()
}

and in the Car.class the method is just a cal to dao.delete(). The thing is that the dao is null. So if instead of the car object being created by Struts, I fetch it from the database, the Car object doesn't get a Dao ovject injected. I thought AspectJ injected the dao on every instance being created, but it's not working on this instance that I fetch from the database. Am I doing something wrong? Is this supposed to work?
Thanks!