I own a 7 openerp server and file translation type po. I looked at all the guides that I have seen under the "Settings" sub category "Translations" option should appear I import / export, while I just listed the "Load Translations"
What should I do to load the translation?
Option Load Translation Loads from all modules from every *.po file in selected language. If you take 'Override' option then it override existing terms. My experience tells me that is not a good methods. If you have your own translations, terms than after that these terms will be overrided by the defaults.
Option Import Translation Most preferable. You know what translates will be overriden and which not because you know your file.
To see the results of imported translations you must restart openerp server. I've noticed also that update/install module also influences on import results. You can try this method without restart your openerp instance, but I wont give you confidence :)