Reverse Proxy via iRules

I am kinda new to F5 iRules and being scratching my head for last week. There's a Virtual Server with https service port that will handle traffic from Internal (VIP is nated on Firewall).

The above part was easy and done but here's the issue. I want to load balance the traffic on nodes but with port 4443 instead of 443 and communicate back externally on 443.

I wrote the below rules but all in vain.

Rule : 1

when HTTP_REQUEST {

  HTTP::redirect "https://[getfield [HTTP::host] ":" 1]:4443[HTTP::uri]"

  }

Rule : 2

when HTTP_REQUEST {

HTTP::redirect "https://172.25.66.103:4443"

}

What I saw that the F5 is communicating externally with 4443 instead. Any help will be highly appreciated.

Thanks