UGH...External Insert noob question

Trying to hook my Mackie 1640i mixer as an external insert to use channel eq on recorded tracks, and cannot seem to make any sense of how this should work.
 
What does work: I have recorded kick drum, and I want to use channel 3 of my Mackie to re eq the track. I set up the output of the recorded track to output 3L of the 1640i. Activate firewire input on that channel on the Mackie, and I see activity on the channel for each kick hit. Now, from here I can create a new track, set the input to be input 3L on the 1640i, arm the track, and record a eq'ed kick track onto the new track. But clearly there is latency, because zooming way out on the tracks show the newly eq'ed track several samples behind the original.
 
So, I want to use the External Insert plug-in so that it does latency correction. With the original drum track still routed out to output 3L I cannot select output 3L on the Insert send selector. I CAN select input 3L on the return, play the original track and see a signal, and even arm and record the insert, but there is no latency correction (the recorded signal is clearly several samples behind the original track). And since I cannot get the insert to ping, I suspect that all I've got going on is a different way of solving the first routing path.
 
What am I doing wrong? Is this even possible?
 
Utterly baffled....