HttpConnector within EmbeddedMode with Neo4j 4.0.0

Hello,
after upgrading my java-code, which starts an embedded neo4j-db (community) within a spring-boot-app, to 4.0 from 3.5 i tried several ways to activate httpConnector (default is FALSE) but all tries failed.

In my opinion it should be as simple as the following lines illustrate:

DatabaseManagementService managementService = new DatabaseManagementServiceBuilder(databaseDirectory)
.setConfig(HttpConnector.enabled, true)
.build();
GraphDatabaseService graphDb = managementService.database(DEFAULT_DATABASE_NAME);

Since i can't find any example for 4.0 maybe i'm just to blind to see what's wrong or is it simply not possible anymore?
Thanks
Klaus