I have my custom listdefinitions up and running quite good but have just some fine-tuning left to do. I would want to add some custom icons instead of those that are used by Tridion. I have defined my own column according to how Tridion does it for his icons.
<list:column id="IconColumn" type="icon" title="" selector="@ItemIcon" width="20" enableresizing="false" enablesorting="false" enablefiltering="false" />
I also added the following to the editor.config:
<itemicons>
<icon match="act\." path="/Themes/Default/Icons/mmIcons/${icon}.${size}x${size}.png" />
</itemicons>
And the icons are available.
The question now is, what do I give as data from the Data Extender to get the icons that I want?