The certificate used for mutual authentication includes a common name (CN) that is extracted and compared to the physical role mapping you create using this CN.
CN=TechnicalUser, OU=sybase, O=sapOptionally, you can use the entire subject as the user name, meaning the whole CN is included, for example, user:CN=TechicalUser, OU=sybase, O=sap.
When using the certificate, ensure the Validated certificate is identity property of CertificateValidationLoginModule is set to true. Also ensure the user maps the entire subject name to the logical role, instead of the CN value.
If you are supporting multiple domains, the mapped user name must also include the named security configuration for either the package the DCN is targeted for or the Admin security configuration for of a Push domain, and appended as a @DomainSecurityConfigName suffix.