What leads to another question: How do I see actually whether a XPCOM interface is a service or not?
I missed the method name, jband gave you and explanation of that. As far as deciding, look at documentation in the code or elsewhere and look at examples. http://lxr.mozilla.org/seamonkey/source/mailnews/mime/emitters/resources/content/attach.js#26 for example.
I'm in the same boat as jband, I don't know much about this class. You'd probably be better off moving to another news group like mail-news. Also try searching google, http://groups.google.com/groups?q=%40mozilla.org%2Fmessenger%3B1&ie=UTF-8&oe=UTF-8&hl=en&btnG=Google+Search that turns up some messages in mail-news.
So how are you running this? It would seem that this needs some component that you don't have registered. Is this JS in a web page, or chrome, or from xpcshell, or somewhere else?
Setting follow-ups to mail-news as this will probably yield more information.
David
