And a few more clarifications:
There is no "Save As..." function (OK, I forgot about this myself), FL4 automatically saves using the same filename.
However, it is safe to rename the file in Windows as the above mentioned checksum only concerns the file content, not the name or date.
As of the means to be sure FL4 is appending to the existing file, here are a few hints.
1) There is no need to save the EXACT configuration in FSX. FL4 has a reasonable tolerance radius when it comes to position. As long as you save the EHF file after landing, parking and shutting down the engine, you may reload the file when parked with the engine off at a different stand on the same aiport.
2) Start FL4 (which will attempt to load and reuse the previously saved flight) after setting the proper configuration in FSX (location, aircraft status etc). OR, after you set the proper configuration in FSX, reload the EHF file.
3) Do not be afraid of the worrysome magenta display! When resuming the flight at a different airport (than origin / destination) it is normal to see "on ground" in magenta
4) You know that the flight is resumed at an intermediary airport when:
- The FSX maeeage appears "Recording flight from... to ..." (the overall origin and destination are shown)
- In the flight details screen, you see details changing (like time, airspeed if there is wind, or fuel burnt)
- When leaving the stand, the FSX message appears "Taxi" (if the ground speed > 5kt)
- The status changes from "on ground" to "taxi" and "climb", as appropriate
5) Also, in the flight details page there is a "Debug" tab that shows a piece of information particularly useful for this kind of flight, the "current leg index". This should read "1" during the first leg, "2" after first intermediate landing and so on.
Hope this helps
Andrei