I don't think that's a good idea, because any friend of you could made these posts for you (with your account). The written exam can only be taken by yourself (identity check).
I took the written exam a long time ago and I don't think I could have refered to any thread/post of mine, because of the detailed information about your solution you (have to) give when answering the questions and simply because I didn't memorize the urls/titles of my threads and posts.
No materials are allowed on the essay exam! And it is not a written exam, it is just like a SCJP exam, except you get 4 open questions (instead of multiple choice ones). So you have only a text box where you can enter some characters. I wish you good luck if you want to draw stuff
You don't have to be afraid of this part of the certification: if you uploaded your assignment, the hardest part is done. The essay exam is really a no-brainer if you have developed your solution yourself. Absolutely no need to worry.