Reverse Proxy setup question

What you want to do is to setup you virtual server on port 80 with a server SSL profile, your pool members on port 443, a HTTP profile, and a rewrite profile. Then you can use an iRule like this to handle rewriting the https links to http back to the client.

when HTTP_REQUEST {
    HTTP::header insert "SetContextURI" "https://[HTTP::host][HTTP::path]"
    HTTP::path [string map {/123/ /321/} [HTTP::path]]
     Disable the stream filter for all requests
    STREAM::disable
     LTM does not uncompress response content, so if the server has compression enabled
     and it cannot be disabled on the server, we can prevent the server from 
     sending a compressed response by removing the compression offerings from the client
    HTTP::header remove "Accept-Encoding"
}
when HTTP_RESPONSE {
     Replace http:// with https://
    STREAM::expression {@/321/@/123/@}

     Enable the stream filter for this response only
    STREAM::enable
}