Hello, I would like to be able to edit and/or upload citation styles to endnote web. Currently, I have to switch to off-line endnote any time I want to use a style that is not available in the web version. Then I have to switch back to the web account in order to add more citations to the document. This back and forth is very annoying. Thanks.
I have the same trouble! Need help 
there is a webpage for Journal editors and librarians to submit requests for new and updated styles here (but not for individuals). They suggest you ask the publishers to request here.