[keycloak-user] Adding properties during token generation

Hello, We are using Keycloak (v2.1.0.Final) in our micro-service architecture. We are currently facing a problem : We imagined adding dynamic properties on the go, into the JWT token, during its generation We already use mappers to put user attributes into token for non dynamic properties. But we would like to avoid putting those dynamic properties into user attributes, or other cold data in Keycloak data models. We really want to avoid duplicating them in Keycloak. Those data are exposed by one of our API, and can be retrieved via a REST call. Is there any mechanism which will allow us to do that ? Thanks in advance for any response. Kilian D