Outlook 2003, setup of LDAP
"Outlook 2003 unavailable critical extension"
Problem with LDAP not working in Outlook 2003 another hint Microsoft Link

registry:
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\LDAP]
"NoDisplayNameSearch"=dword:00000001
"SearchEmailAddress"=dword:00000001
"DisableVLVBrowsing"=dword:00000001

FreeBusy: 
Search: http://manager:kolab@conf.om.org/freebusy/%NAME%.vcf
Publish: ftp://freebusy:freebusy@conf.om.org/%NAME%.vcf