Hi Bruno,
During the final steps of the installation process, the installer allows you to enter the host and port of your database and Elasticsearch index. So long as your server has the permissions to access it, then you should be able to configure a remote database at this stage. See:
Currently the installer is web based, but in the upcoming 2.7 release, we have replaced this with a command-line installer, to avoid timeout issues during configuration that seem to be common with the web installer. If you encounter timeout issues, see this thread for workaround suggestions:
Cheers,