I'm not sure anyone will be able to help but can you be more specific
about what you are trying to do?
In Word 2003 and 2007 "out of the box" you can save in
"WordProcessingML" format - either in a plain .xml file or in the case
of Word 2007, in a .zip format .docx or .docm. If you are using "custom
XML", saving in WordProcessingML format will also save any "Custom XML".
You can also save /just/ the Custom XML. You can also save as XML via an
XSL transform (which you would have to provide yourself, but there may
be some useful ready-made transforms out there). Of course, once it's in
XML format, in theory you can transform it however you like using
off-the-shelf XML tools, but I've always suspected that that is
significantly harder to do with a complex real-world XML file than is
generally believed.
In Word 2007 SP2 you can also save in the .odf XML format.
Maybe you meant something else? What exactly do you mean by "customised
xml files" here?
Peter Jamieson
http://tips.pjmsn.me.uk