vt7 dev release: How to customise modules icons?

In the left-hand vertical menu each module is represented by a flat icon. The markup for each ison goes something like:

<i class="vicon-accounts"></i>

These icons are stored in a svg "font" file.

When we create a new module using vtlib how can we provide our own custom icon for the various places where it is used? Otherwise every vtlib module is always going to have the jigsaw puzzle piece as it's icon...