I found out this by myself :
procedure TForm1.cxButton1Click(Sender: TObject);
var
Memo: TfrxMemoView;
Component: TfrxComponent;
begin
Component := frxReport1.FindObject('Memo4');
if Component is TfrxMemoView then
begin
Memo := Component as TfrxMemoView;
Memo.Text := AdvOfficeStatusBar1.Panels[0].Text;
frxReport1.ShowReport;
end;
end;