Generally the Framework layer is just a template and the real time implementation is your actual application, so the work objects will be created in the implementation class itself. Hope this might help you.
This model gives you the flexibility to use the Framework in other applications, or introduce divisions.
If you create your Work Objects at the Framework level, you lose the reason behind having the Implementation and Framework in the first place.
In the future, if your organisation has multiple implementations using the same Framework, you will currently be able to specialise rules by class for each implementation; Whilst you technically can create Work Objects at the Framework level, this would cause you a world of pain if you elect to extend the application in the future.