I've managed to get FishEye (2.7.5) up and running and working with my Mercurial repositories. I've also got the Jira (4.4.1) integration working and when I browse to a project I see my Changesets in the "Source" panel.
What I don't know how to do is map changesets to issues. For example if I have a Jira issue "ABCD-2123" and a changeset "067768a5d..." in the mapped repository how do I associate them so that the changeset appears in the Activity -> Source tab for the issue?