iRule to replace http with https for specific URLs

I just tested your iRule on an 11.x box and it looks okay. Minor cosmetic modification:

when HTTP_REQUEST {
    STREAM::disable
} 
when HTTP_RESPONSE {
    if { [HTTP::header Content-Type] contains "text" }{
        set find_url1 "http://user.example.net/images"
        set replace_url1 "https://user.example.net/images"
        set find_url2 "http://user.example.net/port"
        set replace_url2 "https://user.example.net/port"
        STREAM::expression "@$find_url1@$replace_url1@ @$find_url2@$replace_url2@"
        STREAM::enable
    } 
}

It changed all references to "http://user.example.net/images" and "http://user.example.net/port" to HTTPS URLs.

And the "/jwp" URL is embedded in the same page and will also be accessible via the same VIP

I don't believe this is true though. An http:// URL will not pass through a 443 VIP.