Eloquent model reflection over a relation method

I am having problems to invoke a relationship method on a model over reflection. My models are:

class User extends \Eloquent
{
    public function city()
    {
        return $this->belongsTo('City', 'city_id', 'id');
    }
}

class City extends \Eloquent
{
}

When I invoke the city method over a ReflectionMethod instance on the User class I am not getting the City model. I think that the problem is involved with the Eloquent lazy loading, but I can't get any light over the problem :( Any ideas?

Thanks in advance for your answers!