This guy figured it out - look at the answer to this question:
http://stackoverflow.com/questions/5...iodical-format
I tried it, it works. Note that Kindlegen will not show you that it is working, it will treat the file like any other book. But if you load it on an actual Kindle, then you will get your articles and sections in the periodical style. This guy is my hero.
And I created an account so I could let you guys know about it. Hi.