private void saveWorkspaceHomeAttr(Element element, XModelObject o) {
   Properties p = o.getModel().getProperties();
   String project = p.getProperty(IModelNature.ECLIPSE_PROJECT);
   String workspace = p.getProperty(XModelConstants.WORKSPACE);
   if (project == null) return;
   String relative =
       workspace.startsWith(project + XModelObjectConstants.SEPARATOR)
           ? "." + workspace.substring(project.length())
           : workspace; //$NON-NLS-1$
   element.setAttribute("workspace-home", relative); // $NON-NLS-1$
 }