Hi @Specail :)
Germany can't deport you without valid papers. That is why Ausländerbehörde wants to have your passport. In case you give it to them you will not be send to your home country (don't worry about that). But they will send you to Italy. There is a European law called Dublin III. It says that Italy is responsible for you because you applied for asylum there first (and by the way, that's also why Germany rejected your second application).
But in general I don't really see how you can stay in Germany legally in the long-run. I mean, with subsidiary protection you are allowed to travel. And I think you don't need a visa for Germany if you stay for no longer than 3 months. But you can't stay or work here with that legal status for longer periods of time anyway :/
All the best,