The trick about opening Discovery in Freelancer Explorer is rather simple. First of all, DO NOT try to open Discovery mod itself. Best way to edit is to:
1) Open FLMM mods folder (usually C:\Program Files\Freelancer Mod Manager\mods) and create a new folder with a name like 'EditDiscovery'.
2) Open Discovery mod folder in FLMM mods. You'll see 4 folders and 6 files (for 4.81). Copy only two folders:
\DATA
\EXE
into EditDiscovery.
3) Launch Freelancer Explorer and open the 'EditDiscovery' thing.
Some things to remember when editing in Freelancer Explorer (I'll write it down in more details later, just a few basics now):
1) Do not trust FLE in creating ANY infocards. Prohibit to edit any DLL files. All strings must be added manually. I used FLE to create jump hole names, but that's one of the few exceptions where FLE handles infocards in a good way.
All names should be saved in a separate text file.
2) Discovery has no space breaks between lines now, to improve performance and avoid some crashes. However, FLE likes line breaks very much and will add them into any files you edit.
This means that YOU MUST NEVER OVERWRITE DISCOVERY FILES WITH FILES EDITED IN FLE. Instead, open the files you changed in 'EditDiscovery', copy the part that FLE added (it's always in the end), paste it into appropriate Discovery ini file and remove all line breaks.
This is especially true about MBases.ini. For example, you add a base. MBases.ini get another entry, but if you simply overwrite Discovery ini with new one, the whole file (largest ini file of Freelancer) will be full of line breaks. So you should copy the entries for the base you added (they are in the very end) to Discovery MBases.ini.
3) Don't trust FLE in general. If it says that a patrol exists, it might crash. Same for encounters. All code that FLE generates must be checked and re-checked manually.
Tip on patrols. Do ALL other necessary editing before adding in patrols. Once the other stuff is done, copy the folder, so you have two copies. Put patrols into the original.
That way if it does crash, you still have the original backup, and you can just delete the non-working version. Starting over from a certain point is sometimes faster than trying to fix it.
Patrols are easier to fix with direct game ini editing, when mod is activated. You find patrol path in the place where game crashes and remove it. If it crashes again, restore the one you deleted and remove another one, etc.
This takes many hours, but testing each patrol after adding it is even more lengthy IMHO.
Patrols are too bad in FLE. Especially Rheinland patrols, these were a torture for me.
I had no trouble adding them into Hessen. It was the infocards that messed up there. Actually.. All my patrols worked.
BTW, I don't think I'll be using the mass of NPC patrols and pop zones like I did in that battlefield system.. Think, 100 ships, GC, Blood Dragon, and KNF fighting.. Its fun to watch though, and even more fun to fight in it.. But alas, would cause to much lag..