Lync 2013 separate FQDN

hello everyone, i've a question about a requisite using the Lync 2013 iApp: the related pdf (http://www.f5.com/pdf/deployment-guides/microsoft-lync-iapp-dg.pdf) on page 4 asks to "Enable separate FQDN and IP address for Web Conferencing and A/V: Checked"

 

this means that i need 9 different IPs on the pubblic vlan.

 

If i disable this option, Does the iApp for Lync 2013 working or not? If yes, how can i use different ports on 1 pubblic IP for this configuration?

 

thanks a lot