SNCPartnerName
In case using SNC with SSO usually the SNC names of the SAP system and your own SNC name are used.
The SNC name of the SAP system can be found in the SAPLogon or also in the SAP system (profile parameter snc/identity/as , visible in transactions RSPFPAR_SNC and SNCCONFIG).
Example: p:CN=SID, O=ACompany, C=EN