To add charms to equipment that has a charm quality, you need to invest in the Enchant Weapon skill.Enchanting weapons/armour/items
There are also a couple quest related equipment upgrades.
The dragon breastplate can be upgraded by the dwarven smith...Silver Armour and Treasure MapsGathering the Holy Items and the Sacrifice
Last edited by Raze; 29/03/13 11:38 PM. Reason: update links