Briefcase file versions

After testing first External import of backed up data, I noticed, that there are no former versions of files or web docs available in Briefcase. Only the last version of file. Is there something special to be done, or we have to cope with such matter?

This is not videly used service in our infrastructure, but more and more we tend to display to our customers, that it is a nice way to keep track on changes. But if such changes are lost during server migrations, this might be a pitfall, or at least introduce some additional actions to be taken, to keep all these versions.