INOTES SSL OFF LOAD WHILE MASKING HOSTNAME OR URL PRESENTED NAME

So you basically want to rewrite server[0-9].mydomain.com to nymail.mydomain.com in the response headers and payloads?

Can you try this rule? You'll need to add the default, blank stream profile and a custom HTTP profile with response chunking set to rechunk for this to work.

http://devcentral.f5.com/Community/GroupDetails/tabid/1082223/asg/50/aft/1178837/showtab/groupforums/Default.aspx

 Example which replaces server[0-9].mydomain.com with the originally requested host in response headers and content

 Prevents server compression in responses
when HTTP_REQUEST {

    Save the requested hostname for rewriting redirects
   set host [HTTP::host]

    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 {

    Check if server response is a redirect and contains the string pattern we want to replace 
   if { [HTTP::is_redirect] and [string match -nocase {http*://server[0-9].mydomain.com} [HTTP::header Location]]} {

       Rewrite the host in redirects to the originally requested host from HTTP_REQUEST
      HTTP::header replace location [string map -nocase "[URI::host [HTTP::header Location]] $host" [HTTP::header Location]]
   }

    Check if response type is text
   if {[HTTP::header value Content-Type] contains "text"}{

       Use a regex to replace server[0-9]\.mydomain\.com with the originally requested host
      STREAM::expression "@server\[0-9\]\.mydomain\.com@$host@"

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

Aaron