IT might be worth adding one thing to your instructions. Before applying the epoxy wipe the usb connector and surrounding PCB area with an ear bud soaked in ethanol (alcohol) or acetone (nail polish remover). This will remove any flux that may still exist on the board from manufacture and ensure a better bond for the epoxy.
It might also be a good idea to try somehow cover the holes in the USB socket to ensure that epoxy does not get into it and prevent the plug from being inserted cleanly. I have been trying to think of a way to acomplish this. One ide is to use very small pieces of blue-tac (http://en.wikipedia.org/wiki/Blu-Tack) since if these get through to the internal connecter they should be harmless and probably come out with the plug next time it is removed.
I intend to do this mod to my N900 this weekend. As they say prevention is better than cure.
Many of us, especially with no experience in hardware modding have no courage to open their 500 euro phone just to make sure it doesn't break. I rather risk my USB port breaking and then returning it to nokia for repairs than void my warranty. Of course it is different in your case as you didn't have the warranty in the first place.