I'm having trouble sharing the missions I create in JA:DG. I can save them and reload them later for editing, but they never show up anywhere in my JA:DG folder.

Oh, solved it. The problem was that Jagged Alliance wasn't being run as Administrator. I right-clicked the icon, properties > compatibility > change settings for all users > run as administrator.

As soon as I did that, any mission I save shows up in the Scenario folder. Unfortunately, I think the missions I created before are unusable because they weren't created while the game was run as administrator.