Help with iRule to redirect to maintenance page with pool is down

Okay, so understand that in this mode the VIP is acting as an SSL proxy. You're doing SSL between the client and the VIP, so you need a client SSL profile on the VIP to handle that communication. You're also doing SSL on the server side, between the BIG-IP and the server, so you need a server SSL profile as well. There are two separate SSL sessions here - one between the client and BIG-IP, and one between the BIG-IP and server, so you need a separate client side and server side SSL profile applied to the VIP. For the iRule to work, you also need an HTTP profile applied to the virtual server. In most versions it's the fourth option down in the virtual server config under the "Configuration" section.