[Mediawiki-l] How do I enable relative paths in templates?

[Jared Brown]

I am trying to setup wikireference.com <http://wikireference.com> so that
new portals can be created in the same way that portals are created on
wikipedia. The problem is that {{/something}} links as this:
"Template:/something" on my installation of mediawiki (v1.4) but as some of
you might know {{/something}} on wikipedia completes the relative path with
the base path you are at. So if you are on WikiReference:Sandbox and you
type {{/something}} it will links as: "WikiReference:Sandbox/something"

My question is:

How do I enable my installation of mediawiki to do this automatically as
wikipedia does?