[keycloak-user] SAML Mappers

Hi All, I am trying to connect Shibboleth IdP as an external IdP with Keycloak acting as an SP. I get the email of the user with friendly name as "mail" back in the SAML assertions. I want to set this as my username for this user in Keycloak. I am attaching a screenshot of my configurations for the mappers which is not working. Maybe someone might have resolved this already or know how to solve it? Thanks, Robin