Redirect to different VS - iRule

If I understand correctly, you want to proxy the traffic going to example.com/example.asp to the http backend server which is already existing on F5.

If this is the case, and while redirecting to a VS should also work, you can instead directly select your existing http pool or more specifically a member of the pool:

when HTTP_REQUEST {
  if { [HTTP::path] equals "example.asp"} {
  SSL::disable serverside
    pool your_http_pool_name member 1.2.3.4 80
     or if you don't want to specify the member:
     pool your_http_pool_name 
    }
}

Note: your example with if { [HTTP::host] equals "example.com/example.asp" } is not correct because the host part is only example.com.