Halo 3 Forge Problems

I remade few of mine favorite maps from Halo 3 that I used to play all the time with my friends, mostly Infection based maps. I haven’t had a chance to test these maps though because you can’t place first-time spawns on the map (like let’s say I made a house where Humans should spawn, but even though I put spawns in there and set them to be Defenders spawns, everyone spawns from a random place).
I noticed too that you can’t place any objectives on your maps such as Oddball’s place or Hill’s positions.
Has anyone made a map in this particular game yet succesfully? I know that H4 has more advanced forge mode where you can do all this but I just like H3 more. And back in the day you could change the gametype while in forge to place any necessary objectives or spawns.