Charming an item and enchanting are completely different things. Adding a charm permanently uses a charm that you found or bought to put a specific bonus on that piece of equipment. An enchantment must be done by an enchanter (or with the machinery in the battle tower) and enchantments can be removed and added as many times as you wish (as long as you have the ingredients for the enchantment - malachite gems are limited, anything else your runners can get as much as you want).
In your inventory, check the level of the Retribution Aura and Static Charge Aura formula (I forget what levels extreme and advanced correspond to), or write down the percentage chance they have of being triggered and damage done.
Next, try to enchant a piece of jewellery with an empty enchantment slot (talk to Bedwyr and say "I need something enchanted."), and go down the list of available enchantments. The two formula you have will either be added or were already there.
In D2:ED I kept a list of all the formula and creature parts I had, to make it easier to keep an eye out for ones that I needed. Before FoV started I had level 9 and 10 of every formula and all perfect creature parts, so could sell anything I found in FoV. I mostly used level 9 enchantments, since level 10 require malachite gems, which are limited in the game. Healing Aura enchantments always use a malachite gem, so I only used level 10 for that jewellery enchantment.
