As in the topic, how does it work / how much mana will you gain, having Mind over Matter?

Details about the question:

• An example for "X % of Damage taken Gained as Mana when Hit": Unique Mindspiral http://pathofexile.gamepedia.com/Mindspiral abbreviated: %DtM
• Mind over Matter is a Keystone and grants: "When Hit, 30 % of Damage is taken from Mana before Life": http://pathofexile.gamepedia.com/Mind_Over_Matter abbreviated MoM

To find the answer, the question is also: Which is calculated first %DtM or MoM?

Simple Example:

• 100 incoming damage and we have no mitigation
• We have 10 % DtM
• We have MoM

There are 2 general possibilities which I see:

1. %DtM first: 100 damage gets you 10 mana first, then deals 70 damage to life and costs 30 mana
2. MoM first: 100 damage deals 70 damage to life and costs 30 mana, first. This results in 7 mana gained (10% of 70 damage to life)