Hi dude, i have the same problem... but i dont think that buying the pro version will be support well openoffice docuements, that problem is between office and openoffice but you can ask to the user what is his word processor and then program two kind of scripts, one made in phpdocx and other made in OdtPhp http://www.odtphp.com/, with this you will able to offer better experience :)
Pd. sorry for my very bad english :S