As in the topic, how does it work / how much mana will you gain? What is calculated first: "% of Damage taken Gained as Mana when Hit" or MoM: "30% of damage is taken from Mana before Life" ?

With other words, which of the follwing is the case?

Simple Example we get 100 damage without mitigation. We wear 10% damage to mana from Mindspiral: http://pathofexile.gamepedia.com/Mindspiral We have Mind over Matter skilled: "30% of damage is taken from Mana before Life".

1. 100 damage dealt results in 10 mana, 70 damage to life, 30 cost in mana
2. 100 damage deals 70 damage to life and costs 30 mana. This results in 7 mana gained (10% of 70 damage to life)