Debian packages install full PostgreSQL server

I've just installed XWiki from Debian packages and found that it depends on and thus installs a full PostgreSQL server. However, I already have an external database server setup for other projects, so I don't need (or better: want) another full server running on the wiki host.

Since the packages also don't ask for database parameters, I needed to manually dump the database after installation, import it on my database server and change the hibernate configuration.

It would be better if the package had specified alternatives for the database connection (like, for example: "postgresql|libpq" and in addition use Debian's package configuration system to ask for database parameters during package installation.