[Zope] Change XML file with zope API

Hi XZoppiste, I'm new in XML but now I can do nice things with the example from Amos in xml.org. I bet on this format, it's too fun ... Now, I'm trying to change a XML via HTML form; I readed the suggestion at the end of the xml.org article and the source code from Builder, Node, XMLDocument, ZDOM but I cannot find a way to write the changes I created in the DOM tree into the XML data file. Is there an integrate solution ? Should I program something by myself ? FR