Thank you Martjin for your reply.
We are using SoapUI 4.5.1-NB-SNAPSHOT and we see the SecurityTokenReference transform in the request. Not sure if that makes sense but I thought I will let you know. Please find attached XML file from the SOAP UI and the error logs from the ABAP back end. Regardless of a certificate present or not in SAP ABAP, we get the exact same error. And, the trace logs show that SAP is using same DSIG_INFO values to compare against Signature(SOAP UI digest) values.
Can you share with us a document or a link, if any, we can use as a reference to set up SAML using ABAP as web service proxy?
Regards,
Pranith.