XBT, Radioloty, please help: Questions about F1 using AP

I'm a F1 student and will visit China for a couple of weeks using my AP. From what Radiology suggested for a similiar post recently, it is not neccessary for me to tell the office of international students. However, I heard any F1 student should get a new I-20 before she/he leaves for other countries.

(1) Do I need get a new I-20 before I leave for China?

(2) If not, what else from the office of international students are needed?

(3) What other documentations do I need for the travel,except the AP, 485 receipt, I-94, and passport?

Thanks a lot!