Hi,
what kind of SSO are you using with SAP NW SSO?
1. If you use Kerberos only -> use the existing Kerberos function in the BOE package
2. If you use X.590 or SAML, you have to configure trusted authentication in BOE -> check docu for "trusted authentication". This means that BOE is trusting the authentication of the underlying application server and here you can configure for example X.509.
Regards
Matthias