Like many of you, I love the new vehicles in UT2k4. I was disappointed to see that they were limited to only a few gametypes. Searching for a way to add vehicles to my maps, I came across the VSOverride actor written by Parser. I built a test map using this actor and, indeed, I was able to use vehicles in my maps. While running some online tests, I noticed that there were a few bugs in team games, most notably with multi-passenger vehicles. Also, with VSOverride, it was not possible to have vehicles locked to a particular team. After a lot of research and reading through the game scripts, I have found an easier and more reliable way to add vehicles to maps, regardless of game type.
check out my tutorial here
I have also recompiled all of the Onslaught vehicle mutators so that they can be used in any game type.
Download them here