Take a look at the enchantments you want to apply. They will most likely have a formlist supplied for the "Worn Restrictions" drop down shown http://www.creationkit.com/index.php?title=Enchantment. If you take a look at that formlist it will show you the keywords you can select from. Usually they select the body slot(s) where the enchantment can be worn, and you pick the one that matches the armor.
The keyword "ArmorClothing" specifies that this armor is neither Light nor Heavy, and "VendorItemClothing" determines who you can sell it to. The keyword that determines what it can be enchanted with is what you need to add.
The body slots in the Armor and ArmorAddon determine where it gets worn, and what is displaces. E.g. does a helmet hide the hair, or the entire head? They don't affect the enchantment restrictions. Only the keywords do that.