WHOA. Awesome idea to add the black padding around the fan as an aesthetically pleasing and easy way to keep it in there. That never even crossed my mind.
Yup, I was happy with that too. Just took some padding from my HDTV, cut to size and then squeezed it in around the fan. This serves a couple of purposes...1) improves the airflow so it only comes in from the front, 2) since the fan is hanging, helps secure it and dampens vibrations, 3) helps with dust around the sides, and 4) looks nice too.