diff --git a/facho/facho.py b/facho/facho.py
index ef39bff..0970c2c 100644
--- a/facho/facho.py
+++ b/facho/facho.py
@@ -184,6 +184,9 @@ class FachoXML:
     def root_namespace(self):
         return etree.QName(self.root).namespace
 
+    def root_localname(self):
+        return etree.QName(self.root).localname
+
     def append_element(self, elem, new_elem):
         # elem = self.find_or_create_element(xpath, append=append)
         # self.builder.append(elem, new_elem)
diff --git a/facho/fe/fe.py b/facho/fe/fe.py
index f62437a..48d11d6 100644
--- a/facho/fe/fe.py
+++ b/facho/fe/fe.py
@@ -105,11 +105,16 @@ class FeXML(FachoXML):
     def tostring(self, **kw):
         # MACHETE(bit4bit) la DIAN espera que la etiqueta raiz no este en un namespace
         root_namespace = self.root_namespace()
+        root_localname = self.root_localname()
         xmlns_name = {v: k for k, v in NAMESPACES.items()}[root_namespace]
+        if root_localname == 'Invoice':
+            urn_oasis = 'urn:oasis:names:specification:ubl:schema:xsd:Invoice-2'
+        if root_localname == 'CreditNote':
+            urn_oasis = 'urn:oasis:names:specification:ubl:schema:xsd:CreditNote-2'
         return super().tostring(**kw)\
                         .replace(xmlns_name + ':', '')\
                         .replace('xmlns:'+xmlns_name, 'xmlns')\
-                        .replace('http://www.dian.gov.co/contratos/facturaelectronica/v1', 'urn:oasis:names:specification:ubl:schema:xsd:Invoice-2')
+                        .replace(root_namespace, urn_oasis)
 
 
 class DianXMLExtensionCUDFE(FachoXMLExtension):