VIP - Load Balancer seems to require more setup than documentation lists

[snm777]

I am running 2.1.5-RELEASE on a virtual machine in ESX 5.5. I think this is where my question belongs, if not, forgive me I could not find a more appropriate part of the forum

I am setting  up a simple load balancer - I have two web servers on the LAN net, and following the directions here https://doc.pfsense.org/index.php/Setup_Incoming_Load_Balancing

WAN IP: 172.16.15.150
Vrtual Server IP: 172.16.15.152
web server 1: 192.168.10.10
web server 2 192.168.10.20

I set up a pool with the two web servers in Services -> Load Balancer -> Pools using their LAN IP addresses 192.168.10.10/20, port set to 80.
went to services -> Load Balancer -> Virtual Servers and configured 172.16.15.152 and associated it with the pool I had just configured.

When I went to Status -> Load Balancer, both the pool IP's and the virtual server showed as up. 
Created a firewall rule to allow the traffic.
At this point, when trying to access http://172.16.15.152, I get nothing. 
Going to the command prompt on the firewall, run a netstat -an | grep 172.16.15.152 , and there is nothign listening on that IP.

I went BACK into the firewall, clicked on Firewall -> Virtual IPs, and there was nothing listed.  So I added 172.16.15.152 as a vitrtual IP, and my load balancer started to work.

This may seem obvious, but it appears that either I need multiple IP's associated with the WAN interface BEFORE I start, or I need to create the VIP under Firewall -> Virtual IP's, not JUST under Services -> Load Balancer -> Virtual Servers.

Is that a correct observation?  Or should the IP automatically be associated with an interface after I create the VIP in Services -> Load Balancer -> Virtual Servers?  If you do have to have the shared IP associated with an interface before you start, that should probably be called out in the documentation.  If creating it according tot he existing documentation is supposed to work as is, it isn't, at least not in 2.1.5-RELEASE on my setup.