My buddy got this game and we started a co-op Imperial campaign together, we played for 23 turns then called it quits for the day. The next day we wanted to resume where we left off but when I load the save, I no longer have an invite button via the steam friends list (since the in-game invite button doesn't work at all).
We did some troubleshooting for about an hour without success, we tried restarting steam, verifying integrity, restarting computers, nothing seemed to work.
Please help as I'd love to continue the campaign with my friend and this is one of the main reasons he even bought the game.