[keycloak-user] access_token always contains JWT

Hi, I am trying to retrieve an access token from a Keycloak (1.8.0.Final) service account by POST /auth/realms/myrealm/protocol/openid-connect/token with grant_type=client_credentials. The result contains a signed JWT as value of field "access_token" rather than a simple token as described in chapter 18 (Service Accounts) of the user guide. So what I expect (need) is a response like this: { "access_token":"2YotnFZFEjr1zCsicMWpAA", "token_type":"bearer", "expires_in":60, "refresh_token":"tGzv3JOkF0XG5Qx2TlKWIA", "refresh_expires_in":600, "id_token":"tGzv3JOkF0XG5Qx2TlKWIA", "not-before-policy":0, "session-state":"234234-234234-234234" } Is there a way to configure the account or the realm to return a simple token in "access_token" (and "refresh_token") rather than a JWT? Cheers, Manfred