item element present in muc#owner query

Hi,

The following stanza sent by Spark is not compliant with the XEP-45 :

<iq id="DQI5x-61"

  to="conf@conference.b.com"

  type="set"

  from="user@a.com/Spark">

  <query xmlns="http://jabber.org/protocol/muc#owner">

  <item affiliation="member" jid="user@b.com"/>

  </query>

</iq>

xsd for muc#owner :

  <xs:elementname='query'>
    <xs:complexType>
      <xs:choicexmlns:xdata='jabber:x:data'minOccurs='0'>
        <xs:elementref='xdata:x'/>
        <xs:elementref='destroy'/>
      </xs:choice>
    </xs:complexType>
  </xs:element>

Regards,

Michel