I'm new to efw, but you can try to add it manually to file '/etc/rc.d/init.d/rc.local'
Add there your static route, and you should have something like:
#!/bin/sh
. /etc/rc.d/efw_lib.sh
route add -net 192.3.52.0/24 gw 172.28.119.53
exit 0
Restart the firewall, and check in Status->Network the routing table.