Absolutely. Simply select "proxy HA" as the proxy mode under the configuration tab. The appliances will show as a single IP address.
Thanks for the Update and Info, but still i have the query will both the appliance handle the traffic in Round-Robin manner, or it would be just active passive.
Like Michael says that active/active and balanced between the appliances: "generally HA is an active/active configuration, that means that bith instance will take traffic and process it. From the two, one appliance will act as a so called director, whereas the other one is backup. The two appliance share a VIP (virtual IP) and decide via VRRP which ones gets traffic. This is steered through the priority setting for HA, the higher one is the primary director, the lower the secondary. Traffic will be balanced between the appliances."