How to set value for checkbox via EmbeddedWB.FillForm ? (Delphi)

Question

Hi , how can i set value for a checkbox via FillForm method ? I tried these but doesn't work :

  W.FillForm('Chkname', 'True');
  W.FillForm('Chkname', '1');
  W.FillForm('Chkname', '', 1);