I have tried again and again to get this solution to work and every time I am stymied by the same issue.
I have create a Virtual Service for port 443. I created content rules for email.domain.com, vpn.domain.com and www.domain.com. I create the SubVS for each domain and added the real servers for each via hostname and every time it resolves it to its IP address. I then apply the proper content rule to the SubVS and then go back to the view/modify section. The VS is always up and at least one of the SubVSs is up but the other two are always down.
Networking wise I have three NICs. Eth0 is on the DMZ, Eth1 is on the Farm, and Eth2 in on the client. I use Eth2 for the management interface