You can use the kdb5_ldap_util utility to update the ldapExtensionInfo attribute on the LDAP server object as follows:
kdb5_ldap_util [-D user_dn [-w passwd]] [-H ldap_uri] [-t trusted_cert] ldapxtn_info -add|-clear
For example:
kdb5_ldap_util -D cn=admin,o=org -H ldaps://ldap-server1.mit.edu ldapxtn_info -add
Table 3-20 ldapxtn_info Parameters