[NTG-context] How do you customize the chapter number format?

I am trying to update the chapter number formatting for the chapter heading. By default the numbering is like 1 First Chapter 1.1 First Section I would like to change this to: 1.0 First Chapter 1.1 First Section Adding the following command worked, except it did not change the numbering in the table of contents: \setuphead[chapter][numbercommand=\groupedcommand{}{.0\blank[2cm]}] Any suggestions for how I change the numbering so that the 1.0 shows up in the table of contents as well? -Lance Larsen