How can i show the tasks list inside the kanban view of the project module?

I tried with an xpath like this:

< xpath expr="//div[@class='o_project_kanban_boxes']" position="after" >
   < field name="task_ids" >
      < tree >
        < field name="id"/ >
        < field name="name"/ >
     < /tree >
   < /field >
< /xpath >

The "id" column is correctly populated, but the "name" colum is empty. How can i solve the problem?