He won't be respresenting me!
Why is "had" required when translating to English? "The lawyer lost the documents" gets the same meaning across
Not really the same meaning; if you ask "why did you fire the laywer yesterday" the answer could be "she had lost the documents". I.e.: saying that something was in the past at a more recent, specific point in the (nearer) past.
I totally agree. As a native English speaker, it would be rather unusual to use "had" in the translation, even though it is correct.