How to set the expanding control in TreeTable on a different column

Hi,

I have this tree table in the example below:

http://jsbin.com/xonacosuvi/edit?html,output

What I try to get is a TreeTable, the first column has checkboxes while the second column has the expandable nodes. The problem is I get the expanding icons [ + ] on the first column which is not what I want. I want to get the [ + ] buttons on the second column.

Is there any way of moving this control from column 1 to column 2?