[NTG-context] Footnote maker in parentheses

Hello, I would like that the footnote marker (both in the note call and the footnote text) appear in parentheses. I tried using : \setupnotation[footnote][titleleft={(},titleright={)}] because the names title* sounded close to what I was looking for, but it did not produce any change (neither in the call nor in the foonote itself). Are those the correct parameters to play with ? Do they need another parameter/option to be set in order to enable them ? Greetings, Stéphane.