STD_HDR_THREAD
HeaderValues[STD_HDR_THREAD] = HeaderValues[STD_HDR_SUBJECT];
SubjectToThread (HeaderValues[STD_HDR_THREAD]);
if (HeaderValues[STD_HDR_THREAD].Length() <= 0)
HeaderValues[STD_HDR_THREAD] = "No Subject";
FileName = HeaderValues [STD_HDR_THREAD];