Empty CMDBuild environment from docker-compose

If I install cmdbuild 3.3 version on a Virtual Machine, I have the possibility to choose between an empty or a demo environment.
In order to have an empty environment from the execution of the Dockerfile, I tried to modify the flag ENV CMDBUILD_DUMP from demo.empty.xz to empty.dump.xz inside the Dockerfile ofthe openmaint-2.0-3.3 version. It didn't work for me.
Have you any ideas on how can I succeed in having an empty environment from the Dockerfile? There are other flags/configuration s that I need to consider?

Thank you a lot!