Custom task is ignored in reports

The new customizable tasks seemed like a good choice to track "to do´s" via the topic properties. But if I use a custom-defined task then it is simply ignored in the "Topic properties" report. Only the standard tasks appear there. I can see my custom task in the "Status" report, but that does not help much because it provides no info about the concerned topics, only their number.

Is this a bug or am I overlooking something?