Thanks for the compliments. I have edited the userbox on your cooperative education wiki so that it is an external link and takes an argument. I would suggest uploading the certificate image to your wiki with an note that it came from Wikieducator and is a CC-BY-SA image.
Will need to think about the category. Maybe create the category on your wiki then in the description page link back to the wikieducator cateogory of the same name.
Nice work by the way!