Assist in Redirecting External URL to Internal URL: Currently Its failing

Still not 100% clear. I'm going to make an assumption here, based both on the requirement to send to a specific pool and that the "ilrwesapp1.jdadelivers.com" URL is not published and accessible, that 1) this URL is internal, 2) you need to change the URI to "/retail" and send to a specific pool, and 3) quite possibly that you need to change the Host header. If that's true, then the following might accomplish that for you.

when HTTP_REQUEST {
    if { [HTTP::uri] equals "/" } {
        HTTP::redirect "http://[HTTP::host]/retail"
    }
    HTTP::header replace Host "ilrwesapp1.jdadelivers.com"
}

If the user accesses the VIP without a specific URI, they'll get redirected to "/retail". The pool assignment is made at the VIP configuration level, so no need to assign it here. The Host header is replaced in the request.