Hi Spoorthy,
I know your reply here is now two years old but it was valuable to me and I would be grateful if you could tell me if your passwords are synchronized between BW and ECC. We are facing the same scenario where Simple Username format has been enabled in BOBJ 4.0, SSO-to-BW is set up as per SAP and BusinessObjects procedures (certificates imported into STRUSTSSO2, etc.) but the SSO-to-BW OLAP Connections only succeed if the passwords in BW and ECC match for the aliased user accounts (both BW and ECC accounts are auto-aliased inside BOBJ 4.0 SP10). When the passwords are mismatched, SSO OLAP Connections to BW fail. We don't know if this is by-design or an issue with how we've configured SSO, but having our passwords match between BW and ECC is not realistic in our present environment.