getting the auth user in php4.2.0/iis5

[Anon]

hi there,

just upgraded a webserver from nt40 php 4.1 to windows 2000 server iis5 / php 4.2.0.

now i can't use echo $AUTH_USER

Any ideas how i can find out who has authorised to the webserver? If i do a phpinfo() i get ;

AUTH_TYPE Negotiate
AUTH_USER WARMOS-NT\markfc
HTTP_USER_AGENT Mozilla/4.0 (compatible; LOGON_USER WARMOS-NT\markfc
NUMBER_OF_PROCESSORS 1
Os2LibPath C:\WINNT\system32\os2\dll;
OS Windows_NT
Path REMOTE_ADDR 2.0.2.55
REMOTE_HOST 2.0.2.55
REMOTE_USER WARMOS-NT\markfc

so it knows that $AUTH_USER is populated and yet when i echo $AUTH_USER it returns nothing.

Many Thanks

Mark