[otrs] No $ENV{REMOTE_USER}

Hi List, I'm try to setup OTRS using Microsoft LDAP as Backend for Customer & Agents. For the Login I want to use Http Basic Auth. By now I can login with my LDAP-User, but when I activate the following lines $Self->{AuthModule}=Kernel::System::Auth::HTTPBasicAuth; $Self->{Customer::AuthModule}=Kernel::System::CustomerAuth::HTTPBasicAut h; I get the following message in the OTRS-Log: [Notice][Kernel::System::Auth::HTTPBasicAuth::Auth] User: No $ENV{REMOTE_USER} !(REMOTE_ADDR: 127.0.0.1). What do I have to do so that OTRS get the current user? I'm using OTRS 2.1.7 + Windows Server 2003 (Apache, mysql) Greetings, david