using QOpenOffice;

Impersonate imp = new Impersonate(ConfigurationManager.AppSettings["user"].ToString(), ConfigurationManager.AppSettings["pwd"].ToString(), ConfigurationManager.AppSettings["dominio"].ToString());

OpenOffice op = new OpenOffice();
op.Load(@"c:\miofile.rtf", true);
op.ExportToPdf(@"c:\miofile.pdf");
op.Close();

imp.UndoImpersonation();