Just as the draftsmen of Papal documents are usually unknown – except in exceptional circumstances – so are the translators, although I noted an exception yesterday.
In 'On Retranslating Humanae Vitae' John Finnis talks about his experience preparing a new version of Paul VI's encyclical. This is on p.344 of his Religion and Public Reasons (Volume 5 of his collected works). You may be able to see this paper at the book's page on Google (it is blocked to me now, it was available earlier). But buy a copy anyway.