You sure can..
You just need to define a different port number in service configuration
In the following example CSS is expecting the client traffic on Virtual ip y.y.y.y and on port 80. Content rule web_servers will loadbalance the connection between server1 (x.x.x.1) & Server2 (x.x.x.2) and "port 8080" under service config will translate the destination port to port 8080.
content Web_Servers
add service server1
add service server2
vip address y.y.y.y
vip-ping-response local-remote
protocol tcp
port 80
active
service server1
ip address x.x.x.1
port 8080
protocol tcp
active
service server2
ip address x.x.x.2
port 8080
protocol 8080
active
Thanks
Syed