How can I configure my Active Directory LDAP server (Windows 2008) to enable certificate verification and client authentication.
I assume that you want to import a certificate from an arbitrary CA. A Windows CA is able to publish certificates directly to an active directory user.
To map a certificate to a user account
Confirm that both the Use Issuer for alternate security identity and the Use Subject for alternate security identity check boxes are selected.
After this, you should be able to authenticate with the certificate against this user. Your application of course has to support Active Directory Certificate authentication.