Need help adding poster username to Plugin [advanced hide mod]

Hey everyone,
I've downloaded the Advanced Hide Mod and I'm trying to make it show up the poster's username in the quote but I haven't got any success with what I've been trying so far, hoping you guys would know the solution.

I'm trying to make it so it says: (poster username) Wrote:
http://prntscr.com/d979rm


I've tried$mybb->user['username'] but that wouldn't work..

I know that this seems as a stupid question, but im stuck with this.