svcutil error: 'SchemaLocation' must successfully resolve if <redefine> contains any child other than <annotation>

Question

I want to generate a proxy class (C#) from a wsdl and some xsd files. The wsdl and the xsd files are all located in the same folder on my disk. The command I'm issuing is:

svcutil.exe AuthenticateAndGetAssertionsSOAP12v2.wsdl .xsd /t:code /l:cs /o:AuthAndGetAssertionsProxy.cs /n:,TestNamespace

but the proxy class is not generated and I get this error:

'SchemaLocation' must successfully resolve if contains any child other than -annotation-.

svcutil also states the document ID with problems is http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd.

One of the xsd files does effectively redefine a complexType defined in this namespace like so:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
    <xs:redefine schemaLocation="oasis-200401-wss-wssecurity-secext-1.0.xsd">
        <xs:complexType name="UsernameTokenType">
            <xs:complexContent>
                <xs:extension base="UsernameTokenType">
                    <xs:sequence>
                        <xs:element name="NewPassword" type="xs:base64Binary"/>
                    </xs:sequence>
                </xs:extension>
            </xs:complexContent>
        </xs:complexType>
    </xs:redefine>
</xs:schema>

I tried fully qualifying the schemaLocation URI like this:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
       <xs:redefine schemaLocation="file:///C:/AuthAndGetAssertionsSOAP12v2/oasis-200401-wss-wssecurity-secext-1.0.xsd">    
       <xs:complexType name="UsernameTokenType">
            <xs:complexContent>
                <xs:extension base="UsernameTokenType">
                    <xs:sequence>
                        <xs:element name="NewPassword" type="xs:base64Binary"/>
                    </xs:sequence>
                </xs:extension>
            </xs:complexContent>
        </xs:complexType>
    </xs:redefine>
</xs:schema>

where C:\AuthAndGetAssertionsSOAP12v2 is the actual path to the wsdl and xsd files, but still I can't get it working.

For reference, this is how the complexType UsernameTokenType is defined in oasis-200401-wss-wssecurity-secext-1.0.xsd:

<xsd:complexType name="UsernameTokenType">
        <xsd:annotation>
            <xsd:documentation>This type represents a username token per Section 4.1</xsd:documentation>
        </xsd:annotation>
        <xsd:sequence>
            <xsd:element name="Username" type="wsse:AttributedString"/>
            <xsd:any processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
        </xsd:sequence>
        <xsd:attribute ref="wsu:Id"/>
        <xsd:anyAttribute namespace="##other" processContents="lax"/>
    </xsd:complexType>

I searched a lot but I couldn't find any solution, but after reading this post

svcUtil error 'SchemaLocation' must successfully resolve if <redefine> contains any child other than <annotation>

I'm starting to think the problem may be elsewhere in the wsdl. Any suggestions?