diff --git a/src/s2repoze/plugins/sp.py b/src/s2repoze/plugins/sp.py
index 02f6334..a80dece 100644
--- a/src/s2repoze/plugins/sp.py
+++ b/src/s2repoze/plugins/sp.py
@@ -496,7 +496,9 @@ class SAML2Plugin(object):
                 # find it
                 environ["post.fieldstorage"] = post
                 # restore wsgi.input incase that is needed
-                environ['wsgi.input'] = StringIO(environ['s2repoze.body'])
+                # only of s2repoze.body is present
+                if 's2repoze.body' in environ:
+                    environ['wsgi.input'] = StringIO(environ['s2repoze.body'])
                 return {}
             else:
                 logger.info("[sp.identify] --- SAMLResponse ---")
diff --git a/src/saml2/response.py b/src/saml2/response.py
index 9f421b8..6e642e4 100644
--- a/src/saml2/response.py
+++ b/src/saml2/response.py
@@ -24,6 +24,7 @@ from saml2.samlp import STATUS_TOO_MANY_RESPONSES
 from saml2.samlp import STATUS_UNKNOWN_ATTR_PROFILE
 from saml2.samlp import STATUS_UNKNOWN_PRINCIPAL
 from saml2.samlp import STATUS_UNSUPPORTED_BINDING
+from saml2.samlp import STATUS_RESPONDER
 
 import xmldsig as ds
 import xmlenc as xenc
@@ -158,6 +159,8 @@ class StatusUnknownPrincipal(StatusError):
 class StatusUnsupportedBinding(StatusError):
     pass
 
+class StatusResponder(StatusError):
+    pass
 
 STATUSCODE2EXCEPTION = {
     STATUS_VERSION_MISMATCH: StatusVersionMismatch,
@@ -180,6 +183,7 @@ STATUSCODE2EXCEPTION = {
     STATUS_UNKNOWN_ATTR_PROFILE: StatusUnknownAttrProfile,
     STATUS_UNKNOWN_PRINCIPAL: StatusUnknownPrincipal,
     STATUS_UNSUPPORTED_BINDING: StatusUnsupportedBinding,
+    STATUS_RESPONDER: StatusResponder,
 }
 # ---------------------------------------------------------------------------