Here are simpler steps to add/delete stuff in a savedgame file with the Editor(MAKE SURE TO BACKUP THE FILES BEFORE YOU SAVE ANYTHING).
Start your mission(in-game) save ASAP(remember the name). Start the Editor open the same mission in F3(Missions) mode, make all your changes and "save-as"(name it anything). Make sure you don't "overwrite" the "0.mi", that's the original.
Now locate the files, these are the paths on my PC, F:game install heremen of warMen of Warresourcemapsingle1 (Editor)
C:UsersjimDocumentsmy gamesmen of warprofilesplayersave (in-game)
Open both files with notepad(MAKE SURE TO BACKUP BOTH FILES BEFORE YOU SAVE ANYTHING) "select-all" on both files, then copy and paste the Editor file into the in-game file then save the in-game file. If done right when you load that savedgame mission you should see your changes. I've done this a lot so I know it works, if it's not working for you, you've done something wrong.