Go to that website, click on the armor that you are building, add in your name and the status of the pieces, and click send. It will save the picture to your computer in whatever your default folder is. Then, upload that picture to your favorite photo hosting site (like photobucket) and use the image code to post it into your signature on the "edit signature" page. That should do it for you.
EDIT: Okay, you move quick. As I was posting that answer, your signature popped up.