[NTG-context] figure in the middle of the page

Hi to all, Sorry if it's obvious. I'm preparing some slides and I'd like to have a figure in the middle of the slide. With \placefigure I place it center-justified horizontally. How can I force to be in the center of the text? Thanks Best -a- Andrea Valle DAMS - Facoltà di Scienze della Formazione Università degli Studi di Torino http://www.semiotiche.it/andrea andrea.valle@unito.it