I also wanted to see General's portrait's for divisions, and I found a way to do it easily. Go to this thread:
http://www.ageod-forum.com/showthread.php?t=4633
Here are the instructions:
This is for people who want to replace the new HQ soldier unit used for unportraited leaders (and their divisions when they get divisions) with the old generic face unit. I find that this makes it easier for me to pick out my leaders and divisions in the game, as they no longer look as much like regular line soldiers.
In order to make this change, it is necessary to change *two* sets of files.
In the folder "ACW\Graphics\Units" you will delete all files that end in "HQDiv1" and replace them with the "generic" portraits. For example, delete "Unit_CSA_HQDiv1" and then save a copy of "Unit_CSA_generic" as that name ("Unit_CSA_HQDiv1"). You will do this five times, for the CSA, USA, ENG, FRA, and MEX files.
Then, in the folder "ACW\Graphics\Armies&Fleets" you will do this (again five times) for the files with names like "Army_MEX_HQDiv1," replacing them with a copy of (for example) "Army_MEX_generic."
The first set of files are the unit portraits for the unit bar at the bottom of the screen. The second set of files are the unit portraits that appear on the map itself.
Remember: BACK UP YOUR ORIGINALS!