Xerces with xs:override

Hi,

I am trying to use xs:override with xerces-j 2.11.0, but I keep receiving the "Element 'override' is invalid, misplaced, or occurs too often" error. 

I am trying to use the example below.

Could you please help me find what might be wrong?

> A.xsd
>  
> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
>     <xs:complexType name="personName">
>         <xs:sequence>
>             <xs:element name="firstName"/>
>             <xs:element name="lastName"/>
>         </xs:sequence>
>     </xs:complexType>
>     <xs:element name="phone" type="xs:string"/>
> </xs:schema>
>  
> B.xsd
>  
> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
>     <xs:override schemaLocation="A.xsd">
>         <xs:complexType name="personName">
>             <xs:sequence>
>                 <xs:element name="givenName"/>
>                 <xs:element name="surname"/>
>             </xs:sequence>
>         </xs:complexType>
>     </xs:override>
> </xs:schema>
> 

Thank you very much