The easiest way is to buy MS Office and Windows, install both in a virtual machine and use that. A comparable way is likely to buy Adobe Acrobat or Adobe Distiller to convert your Word documents to PDF. Maybe Adobe doesn't insist on Windows.

A different way might be to try to automate OpenOffice as it as import filters for Word and export filters for PDF. Unfortunately, OpenOffice is bad to automate unless you like Java and the object model that Java tends to impose.

The most ugly but in the long term most beneficial approach would be to extract the import and export filters from OpenOffice and turn them into Perl extensions or at least command line programs to en- or decode as you want.