I know it's a rather long time ago that this topic was posted, but i am playing ofp again since a long time. I have played the game a lot in the past and I liked it a lot.
So, I downloaded some mods/add-ons like BWMOD, WW2 MOD and some others and I am playing around a bit with the game. I also downloaded the map Ivtiliac and I would really like to play it in Capture the Flag with a friend of my. However the wizard does not include Capture the Flag or any other game play mode for Ivtiliac.
I have tried to fix it by going through your explanation by starting in desert island via MP LAN and then later Mission editor Ivtiliac and merging et cetera, but it does not work for me. I have tried it several times. I end up with a multiplayer mission where you can only select one soldier as a player and the whole script for capturing the flag et cetera does not work at all.
I don't know if you are still on this forum, or someone else is, but I really hope I can fix it, because I would love to play the Ivtiliac map in CTF MP.