[NTG-context] different layout in the table of content

hello I wish to show le numeration differently. if a is the chapter number, b the section number and c the subsubsection chapter number, I write a.bc. L. Cheno showed me how to do this in the head number : ***************************** \def\Numeros#1.#2.#3{{#1}.{#2}{#3}} \def\CNumeros#1#2{\expandafter\Numeros\currentheadnumber\ {#2}} \setuphead[subsection][command=\CNumero] ***************************** Unfortunately this doesn't work in the table of contents. How can we change the look of the numeration in the toc ?