The current CSL processor can't handle this, but it will be supported in the new processor, to be deployed in a subsequent version of Zotero (2.1) sometime in the coming year. You can check out a test fixture that shows the processor doing it correctly here.

This will also be addressed by the new processor, or rather by the new version of the CSL language. Instead of attempting to add periods to short forms of the month names (and other terms), the new processor will take them out when they're not needed.

You might be able to accomplish the same effect in CSL 0.8 by adding a locale block in the style file, redefining the month names used by the style (with periods), and eliminating the add-periods attribute that is producing that stray punctuation. No guarantee that it would be a complete fix, but it might be something to investigate if you're feeling patient and have some time to spend on it.

depends on how involved you want to get - for an occasional fix you can post a link to an uploaded corrected version of a csl style here on the forum and I or someone else will upload it for you.
If you want to get more involved you can get an SVN-trac account
https://www.zotero.org/dev/trac_access
and submit them yourself through SVN

For the editor,
change the line
<label form="short" prefix=", " text-case="lowercase" suffix="."/>
(I suppose in both the author and the editor macro)
so that text-case="capitalize-first"

Generally, a couple of us monitor the style section of the forum and we'll implement stuff the people point out - e.g. I've just updated the IEEE style according to your report https://www.zotero.org/trac/changeset/5733
the corrected style won't show up in the section on the top of the repository, but in the lower section as
http://www.zotero.org/styles/ieee/dev (i.e. with a (dev) at the end).
From time to time Dan pushes the corrected dev styles into the top section and to clients.

It doesn't look like these changes have been added to the release versions yet. What's the easiest way for me to get the dev version of the csl to get the correct IEEE formatting? Also, any idea when these will be included in an update? It's been several months since they were added to the trunk, so I'm hoping that they'll get included soon.

Thanks!

I looked for an IEEE one updated 2010-02-06, but I didn't see it. What's it called? And once I find it, do I just need to click on the "install" link in Firefox and it'll do the rest?

Just got it and tried it out. There's one problem that still hasn't been fixed. Multiple citations such as [14-15] should be formatted at [14]-[15]. Would you be able to fix this? Thanks for all your help.

A couple other awesome features would be the following, which are IEEE formatting requirement:
- Capitalize only the first word in a paper title, except for proper nouns and element symbols.
- Papers that have not been published should be cited as “unpublished” [4]. Papers that have been accepted for publication, but not yet specified for an issue should be cited as “to be published” [5]. NOTE: perhaps could be added as a piece of metadata in Zotero if it isn't already?
.
[4] B. Smith, “An approach to graphs of linear forms (Unpublished work style),” unpublished.
[5] E. H. Miller, “A note on reflector arrays (Periodical style—Accepted for publication),” IEEE Trans. Antennas Propagat., to be published.

Template for all Transactions (except IEEE Transactions on Magnetics, IEEE Magnetics Letters and IEEE Photonics Journal), found at http://www.ieee.org/documents/TRANS-JOUR.doc
Number citations consecutively in square brackets [1]. The sentence punctuation follows the brackets [2]. Multiple references [2], [3] are each numbered with separate brackets [1]–[3]. When citing a section in a book, please give the relevant page numbers [2]. In sentences, refer simply to the reference number, as in [3]. Do not use “Ref. [3]” or “reference [3]” except at the beginning of a sentence: “Reference [3] shows ... .” Please do not use automatic endnotes in Word, rather, type the reference list at the end of the paper using the “References” style.
Number footnotes separately in superscripts (Insert | Footnote). Place the actual footnote at the bottom of the column in which it is cited; do not put footnotes in the reference list (endnotes). Use letters for table footnotes (see Table I).
Please note that the references at the end of this document are in the preferred referencing style. Give all authors’ names; do not use “et al.” unless there are six authors or more. Use a space after authors’ initials. Papers that have not been published should be cited as “unpublished” [4]. Papers that have been accepted for publication, but not yet specified for an issue should be cited as “to be published” [5]. Papers that have been submitted for publication should be cited as “submitted for publication” [6]. Please give affiliations and addresses for private communications [7].
Capitalize only the first word in a paper title, except for proper nouns and element symbols. For papers published in translation journals, please give the English citation first, followed by the original foreign-language citation [8].

It has been a while, but I have reworked the IEEE style to a large extent on my personal machine. It now works well for most common item types (books, journal articles, conference papers, websites) but does not have specific coding in place (yet) for more esoteric things (e.g. theses, patents, IEEE standards).

I don't think I ever did figure out how to commit to the SVN server. Can someone walk me through it or point me to more detailed documentation? Or, I could simply post the updated .csl file here if that would help. It is rather long, though.

Things I have not been able to work around:
* Multiple consecutive citations still show up incorrectly, e.g. "[1-5]" instead of "[1]-[5]". However, multiple separated citations work properly, e.g. "[1], [3], [7 p. 34]".
* Changing the format of a date from IEEE standard (DD-MMM-YYYY, e.g. "01-Aug-2010") to something else when the day is missing but not the month (e.g. "Aug. 2010" instead of "Aug-2010") because I don't know how to use an IF statement check if a specific part of the date is present.
* Dates in MMM. YYYY format (e.g. "Aug. 2010") won't work correctly for the month of May, which will get a period (as in "May. 2010" when it should be "May 2010").
* The style can distinguish between published and unpublished conference papers by whether or not a conference proceedings title is given, and will prepend "presented at the" for unpublished papers. Unfortunately, if the proceedings title begins with "The", then you get two "the"s.

Also, the style as I have it does not address things like "unpublished" or "to be published"; those have to still be worked around manually.

Ok, I have added the "rights" tag and created a code snippet at: http://gist.github.com/551561.

I noted that my XML validated fine before adding the "rights" tag, but now that the "rights" tag is in place it does not validate any longer. I'm not sure I put it in the correct place in the XML.

As I mentioned before, I want to emphasize that not everything is implemented in the updated style. However, it should work better than the previous one for a significant number of citation types.

(About SVN, I signed up for an account, but haven't been able to find instructions for where specifically the repository is located so I can point to it. I've found the trac stuff, but that seems to just be online summaries of changes.)

Ah, got it. I missed that it was a closing "info" tag; I put it outside of "info". I'll edit the gist. I can try the SVN access again later today or tomorrow.