Transparent port redirect

Hey Guys,

I've received a request to setup a VS listening on port 443, as well as on a range from 18500 to 18550 included. If a request comes in on port 443 it must be passed to the backend server on port 8443 instead (standard port translation). But if the request comes on a port between 18500 and 18550, then there's no change needed. I've came up with the below iRule, but I don't know how to address the transparent 443 to 8443 translation.

when CLIENT_ACCEPTED {
    if {([TCP::local_port] >= 18500 ) && ([TCP::local_port] <= 18550)} {
        pool MyPool
    }elseif {([TCP::local_port] equals 443 )} {
        <-- here I need to change to port 8443 -->
        pool MyPool
    } else reject
}

Could you help me out, I don't know how to achieve this. Thanks