Xalan - node.setNodeValue(String)

[Grégoire Berclaz]

Hello,
I need xalan and read xml files with. Now I would like to edit a node. I select this node with

 Node node = XPathAPI.selectSingleNode(doc, "/*/logo") ; 

Then I set a value to this node

 node.getFirstChild().setNodeValue("myLogo.gif") ; 

Then I check it

 System.out.println(node.getFirstChild().getNodeValue()) ; 

and it wrote : "myLogo.gif"
If I open my xml file, the (only) node "logo" hasn't got a value...
What my problem? Why the string "myLogo.gif" isn't save?
Gr�goire Berclaz