Fully Qualified Name: org.picketlink.identity.federation.web.config.SPPostMetadataConfigurationProvider
Binding Supported: SAML2/HTTP-POST
You will need to provide the metadata file inside sp-metadata.xml and put it in the SP web application classpath. Put it in WEB-INF/classes directory.
Remember, in the case of SP, the metadata file should have a IDPSSODescriptor as well as a SPSSODescriptor.