Здравствуйте, sowell, Вы писали:

 TStreamHeader = record
    case Integer of
      0: ( { New }
        Signature: Integer;
        DrawAspect: Integer;
        DataSize: Integer);
      1: ( { Old }
        PartRect: TSmallRect);
  end;

 if FOldStreamFormat then
  begin
    R := BoundsRect;
    Header.PartRect.Left := R.Left;
    Header.PartRect.Top := R.Top;
    Header.PartRect.Right := R.Right;
    Header.PartRect.Bottom := R.Bottom;
  end else
  begin
    Header.Signature := StreamSignature;
    Header.DrawAspect := FDrawAspect;
  end;
  Header.DataSize := GlobalSize(DataHandle);
  Stream.WriteBuffer(Header, SizeOf(Header));
  Buffer := GlobalLock(DataHandle);
  try
    Stream.WriteBuffer(Buffer^, Header.DataSize);
  finally
    GlobalUnlock(DataHandle);
  end;

Записывай со смещения SizeOf(TStreamHeader)