Convert Word document to HTML

I've found two ways to convert a word document in docx format to HTML, both using XSLT.

• Sharepoint's DocX2Html.xsl, no idea if it is open source
  
• xslt on OpenXML

This would make it possible to do some kind of mail merge preview, replacing the mail merge fields and showing the output both using XSLT.


Similar topic, but different implementation (not open source) from Softinterface. Not sure how they get this working without installing any additional software. (perhaps they use the OLE object's preview for images, but how about the entire Word document?).