FYI ... Its a lot simpler in MS's SQL Server and SAP's ASE DBMS as I just need to connect with a known DB user id + pw or use Windows authentication from an Application server - then pass the real windows login user id in the DBParm as follows:
SQLCA.DBParm = "AppName='<MyApp>',Sec_Network_Auth=1,Host='<PC Signature>"
This now allows SSO with ASE / SS being able to track the real user id, application and workstation that this connect represents. I'm not sure if Oracle supports this equivalent functionality in newer releases.