SAML - IdP Initiated, Artifact Binding Authentication

Looking for solution or sample code for SAML http-artifact binding

We are considering to use spring-security-saml2 and our requirement is

1. After retrieving the SAMLart from the HTTP request
2. We need to frame signed ArtifactResolve(SOAP) using the SAMLart and send it IDP via a back end SOAP call
3. SP and IDP Metadata are predefined

Could you please give me some sample code how to generate signed ArtifactResolve(SOAP) using the SAMLart, your help is greatly appreciated. thanks in advance.