Well, this list already saved me some time & good money. Three days ago I was asking how much customs charge here in Canada for buying stuff from US and a member contacted me to sell me the very same lens I was looking for, which I don't find used very often or for which, as usual, local dealers try to sell for a nice ripoff price.
Many thanks to Greg Cooper for the smooth transaction and thanks to Aaron, Powell and Wendy for your answers regarding customs; I'll use your tips in the future, once I save enough money for the DA 16-45. Cheers. Fernando