add more than one namespace in XML

hi

I am generating XMl file using XmlEans. I have written :

File outputFile = new File(RSSFile);
XmlOptions options = new XmlOptions();

options.setSavePrettyPrint();
options.setSavePrettyPrintIndent(2);
Map m = new HashMap();

m.put("xmlns:n","http://www.w3.org/2001/XMLSchema-instance");
m.put("xmlns:nav","http://g.sys.com/rss/nRSS");
options.setUseDefaultNamespace();
options.setSaveAggressiveNamespaces();
options.setLoadAdditionalNamespaces(m);
rssDoc.save(outputFile, options );

but it is not adding this two namespace in the XMl file. It only add the default namespace.How to add mroe than one namespace?