I have been looking on google for anyone that is using the Barracuda 340 and some tricks in the setup and nothing. The documents on the load balancer is rotten. I will say the support people are great and a great help in the configuration of the unit. If you configure one setting wrong and BAM broken service. 
I have two MySql servers setup in a master master configuration. I wanted to have both servers able to take connections so I setup HAProxy 1.4.11 to manage the services.
Web servers are using Barracuda 340 Fireware v3.5.0.008 configuration with Layer 7 on both port 80 and 443 and MySql services are managed with HAProxy 1.4.11 configuration for the load balancing connections:
global
log 127.0.0.1 local0
log 127.0.0.1 local1 notice
#log loghost local0 info
maxconn 4096
chroot /var/lib/haproxy
user haproxy
group haproxy
daemon
#debug
#quiet
defaults
log global
mode http
option dontlognull
retries 3
option redispatch
maxconn 2000
contimeout 5000
clitimeout 50000
srvtimeout 50000
listen MySQL 123.456.789.100:3306
mode tcp
http-check expect ! string SQL\ Error
balance source
server mysql_slave 123.456.789.200:3306 check port 3306 inter 12000 rise 3 fall 3
server mysql_slave 123.456.789.300:3306 check port 3306 inter 12000 rise 3 fall 3
listen stats 123.456.789.100:80
mode http
option httpclose
stats enable
stats uri /
stats auth user:thepassword
stats refresh 1s
balance source