Software :: How To Digitally Sign Doc Created With Word Processor

I am looking for an easy way to digitally sign documents produced with regular word processors. Here are my findings so far:LibreOffice and OpenOffice are ready to digitally sign documents. There are a few steps involved (such as obtaining the certificate). For documents produced with a different word processor (such as Abiword), there is always the option to transform them into pdf documents, which seem to be ready to be digitally signed, with specific software. The first thing I looked at was gpg, which allows for a detached signature and also for a "clearsign" option, which attaches the signature to the document.

I have already ruled out the "detached signature", as this imposes another degree of difficulty to handle a stack of documents that will need to be classified and relocated frequently. As for the "clearsign" option, it is great for simple text documents but, when used with Abiword documents (for instance), the few extra lines outside the xml tree renders them impossible to read. So far, forcing all my coworkers to use only LibreOffice seems to be the simplest alternative.