userCertificate, wrong attribute type?

Hello,

Using OpenLDAP 2.4.12 (SLES 2011 SP1), I am trying to add a userCertificate attribute to an existing user (inetOrgPerson object).

I converted the PEM file containing the certificate to DER format, then created this ldif:

dn: cn=Nicolas.Kowalski,ou=people,dc=home,dc=lan changetype: modify add: userCertificate userCertificate;binary:< file:///root/ssl/Nicolas.Kowalski-crt.der

But when I try to update the entry, I always get this error:

# ldapmodify -x -W-D "cn=Manager,dc=home,dc=lan" -f the-ldif-above ldapmodify: wrong attributeType at line 4, entry "cn=Nicolas.Kowalski,ou=people,dc=home,dc=lan"

What am I doing wrong?

Thanks,