I installed the IM gateway last week for the first time and I think it a great plugin. The only problem I found is that the spanish translation is not working OK. The unicode escape codes in the file look like stange symbols in my browser (only tried with firefox and konqueror).
Anyway I made a patch so that the file looks like the main openfire spanish translation file (which I did myself by the way) and translated some not yet translated phrases and corrected some spelling errors. So, now it does not have unicode escapes and is an ISO-8859-1 encoded file.
If you are insterested you could apply it to the trunk free of charge