Hi,
This looks like a standard OpenOffice document in XML so the data includes details of how the author intended it to be displayed?
If so it also looks as if there are already XSL files available to convert it to XHTML at
http://xml.openoffice.org/sx2ml/ - but I don't know whether MSXML supports the required features....
It also looks as if OO has a 'web wizard' which can do this for you but I don't know if that will help you - I don't remember whether you specified whether this was to be a one-off process?
Regards,
Viv