adding x-hidden denied

Hi,
I am trying to add x-hidden to the olcAttributeOptions attribute type
but I always get error 80,

:~> ldapadd -D cn=config -w xxx -H ldap://localhost
dn: cn=config
changetype: modify
add: olcAttributeOptions
olcAttributeOptions: x-hidden

modifying entry "cn=config"
ldap_modify: Other (e.g., implementation specific) error (80)
	additional info: <olcAttributeOptions> handler exited with 1

:~> ldapadd -D cn=config -w xxx -H ldap://localhost
dn: cn=config
changetype: modify
replace: olcAttributeOptions
olcAttributeOptions: x-hidden lang-

modifying entry "cn=config"
ldap_modify: Other (e.g., implementation specific) error (80)

Any idea how to add this attribute value? Or is x-hidden not
supported?

-Dieter
 -- 
Dieter Klünter | Systemberatung
http://dkluenter.de
GPG Key ID:8EF7B6C6
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