Joe,
Sorry I can't help with attaching a keep alive... you will need someone that knows the PCB to tell you where you can make the connections. Here's a pic of the top board (and part of the under board) of the decoder:
Since there are no other lighting effects (unless you have added some?), from the Economi manual, it looks to me like you can make the headlight directional by programming C57=1 (headlight forward enable) and CV58=0 (headlight reverse disable). If you have added other lighting effects, you will need to add values in the other bits corresponding to how you want to control those effects. See pages 51-52 of the Economi manual.
Another option would be to make the headlight "autodim:" If I understand the manual correctly (pp 47-49), if you set CV49=1, when the loco is stopped or moving in reverse it should autodim to a value set in CV63 (0= 0% brightness, 255 = 100% brightness). I use autodim on all my current (Tsunami-equipped) locos, but never used it on my Economi 2-8-0 because the headlight was so dim it could barely be seen anyway.
Good luck! Dave