This is what I've got. Whip the raw sausage in a mixer with a paddle with something that will loosen up the consistency; maybe some cream, stock, a bit more fat, etc. Put the mixture in a piping bag either tying it off, or using the cryovac. Poach it until the sausage is just done and ice it down. Cut the tip of the bag off, make your little incision in that breast, and pipe away.
It just came to me that the finer the sausage grind, the better the cooked sausage will pipe and set up. Maybe you could run the sausage through the grinder a second time to give it the stability of a forcemeat, while keeping the integrity of the sausage?