How do I renew my STCW95 Certificate Online?

Hi, I am holding a current STCW95 certificate which will expire on the 8th of December 2015. I have read and heard a lot of advice. However its all very inconsistent. Do I have to retake my STCW95 in order to get a valid 5 year certificate or can I renew my old one somehow. If yes is this possible online? Any help is appreciated.

Thanks guys.