Trigger when you respond to an email

[mysticalh2o]

Why can't we define a trigger for when we respond to an email from a specific address? In this case, I want it to log a copy of the email in my One Note. But it won't let me define a trigger for a reply. 

If I'm just not understanding how to do this, and someone would take pity on me, I would greatly appreciate it. 

TIA