There is currently a bug in external DJ repo that causes all custom (non-standard) schema attributes to be treated as strings. To properly support additional types we need to specify the schema when creating the LdapConnectionFactory during bundle activation
I've had a chance to look in more detail at how Rest2Ldap uses the schema. In fact, it depends on the schema that is being used by the underlying LdapConnectionFactory. This can be configured when the connection factory is created by setting the DecodeOptions. See CommonLdapOptions#DECODE_OPTIONS. In other words, it's up to the client application to fetch the schema from the server (or from files).