Irule for inserting client Ip information

You can add an irule to insert the client source IP either via a cookie insert or using a X-Forwarded-For header... some quick examples below

Code   when HTTP_REQUEST {
 HTTP::header insert X-Forwarded-For [IP::client_addr]
 log local0. "Client IP:  [IP::client_addr]"

}

or

Code  when HTTP_REQUEST {
 Insert a cookie named CUSTOMER_IP with the client IP address as a value
HTTP::cookie insert name CUSTOMER_IP value [IP::client_addr] 
 }

I tested both and they work fine with SNAT configured