I think you will find it much easier to generate a
RTF formatted document than a .DOC format.
The Apache FOP toolkit can generate .RTF as well as several other output formats. An .RTF document should be accepted by
Word, Open Office, Star Office, etc. wp programs.
Most people use FOP to generate .PDF documents but the basic idea permits generating other formats.
As far as I am concerned, Microsoft has in the past deliberately made their word processing formats hard to understand and implement. Under pressure from big users they appear to be taking steps toward an "open" XML based format.
Bill