Hi Paolo,
Welcome to the ranch. First, please don't cross post your questions. Some ranchers who read several of the forums will get annoyed by cross posts and may be less likely to help out. Also, it makes it hard to follow the conversation when people are posting to two different places.
Now, with regards to your question...
My first suggestion would be to save the documents in xml format and parse through them like that. Microsoft
Word 2003 and later have the ability to save into XML format, and it is pretty easy to parse through and populate whatever variables you need to before printing off the document.
There are also some APIs out there that can read Word documents. Off the top of my head, I believe the JACOB project, Jakarta POI, and OpenOffice all have API that can read and manipulate Word data. Google them and see what you come up with. Good Luck, and if you have more questions, ask!