online_update behind proxy with squid

using suse pro 7.3 YOU does not work behind a proxy even I'dd set up http_proxy & ftp_proxy in /etc/rc.config or /etc/wgetrc in any combination possible from squid logs I get succesfull attempt of getting serverlists file from different online update SuSE servers. If I am using masquerading and not proxy everything works fine... but I really need some caching ... allmost 100 SuSE 7.3 pro stations behind proxy waiting to get updated ! 10x in advance