There's no question here, but as someone who extensively uses LTM with Lync 2010 / 2013 I'll give you some info.
The reason you need to use real public IP addresses is the SIP traffic that Lync sends/receives. Lync hardcodes the real IP address within the SIP packets so if you use any kind of NAT on it, it ceases to work. You must use three public IPs for your Edge pools - one each for AV / Webconf / Access - and each Edge server has one IP for each. So if you have two Edge servers you need 9 public IPs, if you have three Edge servers you need 12, and so on. This is per pool as well, so if you've got another pool you'll need 3 more public IPs.
Hopefully this will help explain why, please say if you need to ask more.
Nimbostratus