@fbueckert: Take a look at the answer in the other question. It describes what Cross-Play and Remote-Play is. However both features are not compareable to using a PS Vita as an additional PS3 Controller, like I want to do. This is why both questions are aiming for similar, but basicly different topics!

Thanks for your answer :) What about my second question? I've edited the question, so does the moderator see my edit to be able to review it?