virtual command not working

I believe your problem is that where the guide says to create an "internal virtual server", it means a standard virtual server that is internal to your network, not a virtual server of type 'internal'. I'll get the article updated to make that clearer.

Internal virtual servers (or IVS), which is a virtual server of type 'internal' are used for sideband connections to ICAP servers, APM flows, etc. They can't be selected with the irule 'virtual' command (you'll get a reset cause of '{peer} host unreachable' if you try to do it)