Hopefully the other damage types will be hooked up soon.
That doesn't make any sense. They're already functional in the game. What you are seeing is probably from a time before when they didn't have the damage types in pure xml. They do now.
The thing is that I did a LOT of experimenting with these random tags that don't exist in the core xml files, back when I was doing E:wom mods. And I can't think of a single example that I ever got to work. I also chatted with Cari_Elf about it on a weekly basis, and asked about tags, and the answer was either "that isn't hooked up", or "that doesn't work like that".
My advice is to stick to what we see in the core xml files. There's no magic fairyland to discover. They coded what they needed to make the core game work. The rest is unfinished, or unused, or commented out.
If you want to push the envelope, try to think up new ways that you can use or combine the existing systems to create interesting functions. Such as http://forums.elementalgame.com/417219
PS. Many tags from E:wom are still present and functional in FE.exe. So if a tag worked in E:wom there's a large chance it'll work in FE.