You guys are having problems because of how the armor.ini is constructed. If you go into your itemtype.dat, copy the id for any armor, then search it in the armor.ini, you'll see you don't find it. Even if you copy the id for a texture or mesh, then search it in the armor.ini, same deal. To be honest, I don't even know if it's what is required to get the armor to show up. I just started making one myself, and realized, it's not going to work. I'll continue looking, incase I can figure it out, but I really don't know if I will... Armor was always the one thing I couldn't figure out how to add to the game.
Edit: Ok, well I think I may be on to something. Here is what you guys should look at. Now keep in mind, each piece of armor comes in 8 colours, so there will be multiple textures. I'm going to use one trojan armor as an example.
When you look at the ID for HardArmor, it's 130313, now if you go into you c3 textures folder in the client, you will find the texture, with the id 003130310, if you remove the 003 at the beginning, it's basically identical, except the last number (which indicates quality on the itemtype), because quality I would assume is pointless when it comes to the image correct (it's only important for weapons based on colour change)? So now, if you search in the armor.ini, you will find 1130310, which is the texture id, with the 003 at the beginning being replaced by a 1. I know this is confusing, but paying attention to these small details and variations could very well help to make a piece of armor. I'm going to test my theories on this a bit further, but I won't be making a guide after (that is if it works). I'll leave that to DragonStar.