New conf.json setting "worldsIgnorePvP" as a list of worlds which you don't want Factions to pay any attention to PvP in. No new command has been added to set this, since we now have the /f config command. So, to add/remove worlds, simply use /f config worldsIgnorePvP [YourWorldHere].

src/com/massivecraft/factions/Conf.java

@@ -164,6 +164,7 @@ public class Conf {
 	
 	public static Set<String> worldsNoClaiming = new HashSet<String>();
 	public static Set<String> worldsNoPowerLoss = new HashSet<String>();
+	public static Set<String> worldsIgnorePvP = new HashSet<String>();
 	
 	public static transient int mapHeight = 8;
 	public static transient int mapWidth = 39;