Keep subdomain in FQDN node

The FQDN for the pool member will just make sure that the pool member IP is not static and will follow any changes in DNS, so pool member traffic will always be routed to the right IP address.

I think the issue your are having is that you website is expecting traffic destined for the FQDN not the IP. This is actually signalled to the website by the HTTP host header in the HTTP requests, which is taken from what you type in the browser. So if you type the IP in the browser and go the web server it rejects the traffic as the host header = xx.xx.xx.xx IP. If you type in tlstest.paypal.com in the browser it works as expected. When you type F5 VIP in the browser you are again setting the Host header to an IP address so when this is passed to the website it is not accepted. You can test this out by adding a hosts file entry on your client mapping the F5 VIP to tlstest.paypal.com and then browsing via the hostname. There may be various ways to achieve what you want depending on your environment. You could add internal DNS entries, set hosts file entries if it's a one off test setup or even use forwarding VSs.