Splunk SAML Unable to parse the payload received as a part if idp metadata file or xml.

We tried to enable SAML authentication for our 6.3.1 splunk SH. For this we tried to import the IdP metadata xml file, but this fails with the following message : "Unable to parse the payload received as a part if idp metadata file or xml." We tried to import the IdP xml file provided at Step 3 "Obtain the IdP meta data" of this blog : http://blogs.splunk.com/2013/03/28/splunkweb-sso-samlv2/ but we do obtain the exact same message : "Unable to parse the payload received as a part if idp metadata file or xml." Is there a specific format we need to comply to ? Any help would be very much appreciated. Thanks