Can't Add Categories to Custom Homepage

[joes]

Hi,
Im trying to add a list of categories to my custom homepage template using:

<h1>homepage header</h1>
<!-- IMPORT categories.tpl -->

however - instead of a list, it just outputs:

No new posts.

Im using a custom theme based on persona. The h1 tag renders fine..

Any help would be appreciated.
I suspect I need to add in the categories data in somewhere.. but can't find any documentation on this..

Joe