[Zope] security and domain

hello zopers, Here is my situation : I have a zope hosted behind apache and virtual monster When i need the ip address of a visitor I use HTTP_X_FORWARDED_FOR I want some users to log only from a specific IP for example : 100.100.50.25 If I set 'domain' in the acl_user fiels to that IP, it doesn't work, I guess the domain it returns is the domain of the Apache or proxy server. Is there a workaround for the domain to be checked against the HHTP_X_FORWARDED instead of the IP_ADDRESS ??? Any help or pointers is welcome...