In some environments (e.g. production) it is not allowed that applications create their own schema. It's common practice to pass DDL-Statetements to DBAs instead prior to rollout.
Currently the broker does not support this scenario. If the required tables already exist the broker fails to start.
A better approach is that if the broker detects empy tables and initializes them in the very same way it does if the tables dont't exist.
See also discussion in forum.