It's not an either/or proposition, but the e-smith-imp version I have up there is for SME 5.1.2, not 5.5. I'm sure I've posted this before, but here's what you need to do:
# /sbin/e-smith/expand-template /home/httpd/html/horde/imp/config/servers.php
# /sbin/e-smith/expand-template /home/httpd/html/horde/imp/config/conf.php