For the diplomacy settings, just manually unlock teams before you load the scenario and tell the players to switch teams.
It's annoying to tell people what civ to be since most of them don't want to do it... But, it is possible to get a game started.
I have a scenario that I made called Fortress and the civs must be Zeus, Hades, Poseidon for each team and the players always have problems but after 10 min I can get a game started.
I keep that scenario to my self because it is so hard to host but it is nice to play once in a while.
[This message has been edited by Mojo14 (edited 01-28-2003 @ 00:34 AM).]