When I wrote the original periodical information I didn't know much about periodicals (I probably still don't
) having only downloaded a couple to try.
After noticing that my list of book titles in the view collections report was showing the wrong number of titles for periodicals I did a bit more investigating (my Kindle files are a mess now and I'll have to remember to unsubscribe from the 14 day trials I signed up to
). After quite a few blind alleys I've found that the mobi files actually have 2 places where they encode the type of a file (fairly obvious if you look at the mobi format wiki here on Mobileread but I tend to jump in and try it to see what happens first
) (Looking at the wiki also helped me find that some files were in an old mobi format called palm doc which is why titles weren't showing up in the Edit list so I've been able to fix that).
I was originally using the cdetype in the extended header to tell if something was a periodical, but it turns out that the Kindle is mainly using the main type in the mobi header. This means it is not necessary to play around with cdetype/[PDOC] for Periodicals. (Its still necessary for Catalogs and News Feeds). And its not necessary to edit/delete Periodicals to put them into collections. But for 1.4.3 I'm blocking you from doing this because it looks at the wrong type when checking if you can put it into a collection.
So with the next version you should be able to just select the periodical and put it into a collection using Edit. Or if you import it into Calibre, just use create to put it in a collection, though I need to see what happens with the old file. Duplicate codes and titles confuse things - so I've added a section to the report to identify these for checking (along with invalid extensions) - sort of a quality check on what's on your Kindle.
With the right type field being used, and figuring out what files and cdetype's the Kindle ignores I can now identify which periodical should be listed in the main title list, and which should be in the Periodical Back Issues list (just to make the report look more like the Kindle's view). Can't figure out how the Kindle sorts books by most recent though - it stores some of this internally and some in mbp files - but that's not important to most uses.
Since the Kindle deletes older periodicals unless you save them though, if you put a periodical in a collection and the Kindle deletes it, you're left with an entry in the collection that has no file. I do highlight these in the report and Edit for cleanup - but since dictionaries and some other Kindle books have no files in the filesystem either, its difficult to tell what should be removed or what should be left except by looking at the collection on the Kindle for the title and comparing.
Oh, and so the answer to your question is, best to wait for the next version for the periodical stuff