[Code]
var
  MyButton: TNewButton;

procedure MyButtonOnClick(Sender: TObject);
begin
  MsgBox('This is a demo of how to create a button!', mbInformation, mb_Ok);
end;

procedure InitializeWizard;
begin
  MyButton := TNewButton.Create(WizardForm);
  MyButton.Parent := WizardForm;
  MyButton.Left := WizardForm.BackButton.Left - 122;
  MyButton.Top := WizardForm.BackButton.Top;
  MyButton.Width := 120;
  MyButton.Height := WizardForm.BackButton.Height;
  MyButton.Caption := 'Do something';
  MyButton.OnClick := @MyButtonOnClick;
end;

procedure CurPageChanged(CurPageID: Integer);
begin
  MyButton.Visible := CurPageID = wpSelectComponents;
end;