Don't worry. I have actually tried several forums. Basically I haven't worked with Box2d before, so anyone can suggest a thing that might help :)
The body will be definitely Dynamic - it already is. I guess that part I got quite easily. I wasn't really sure what for the impulses are so I will try to use them and see how it behaves.
To dampen the effect of forces I already use quite harsh damping, but I'm afraid it will have a negative impact on the blasting / knocking away behaviour.
Finally, I have come up with an idea yesterday, not sure if it is going to work. That I would always take the linear and angular velocity and in case of detected movement I would add/substract something and then set it, but as you say and as well as it is
written at many places, messing with setting velocity and position manually is not the clear way to do things.
Thanks for your time, I will consider and try your "using impulses" suggestion.