Cite-o-matic sorting does not work

I am trying to use cite-o-matic to include bibliography in Word. I would like to use IEEE style but the sorting needs to be based on the last name of the first author. I edited the IEEE style in Visual CSL Editor. I simply removed the default sort option and added "sort by author". However, it still keeps sorting based on the order that I included the citation in the document. The first citation that I add becomes the first reference and so on. Does anyone know hot to fix that problem? Thanks