As mentioned on the free/open source software for translation page, both LibreOffice and OpenOffice (the project from which it forked) can have their functionality increased by plug-ins known as extensions.
Of the extensions I’ve tried so far, my favourite has to be MultiSave. MultiSave enables a file to be saved in up to 3 formats at once: ODF, MS Office and PDF.
As I always work in ODF, but usually return work in MS Office format and submit my invoices as PDFs, you can imagine how much time this has saved me.
Give it a try! I recommend it.