How to move namespace declaration from inner element to upper element?

Question

I have a java + spring boot app. I'm using jaxws-maven-plugin to generate sources based on .wsdl and .xsd files. I'm sending a soap request receiving response. Unfortunately the response is not 100% the same as expected example that I have from the client.

Expected response:

<soapenv:Envelope">
   <soapenv:Body>
      <wst13:SecResponse">
         <wst13:SecToken>

            <saml:Assertion ID="A-123"
                    xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
                    xmlns:xsd="http://www.w3.org/2001/XMLSchema"
                    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
               <saml:AttributeStatement>
                  <saml:Attribute Name="ClientID">
                     <saml:AttributeValue xsi:type="xsd:string">hello</saml:AttributeValue>
                  </saml:Attribute>
               </saml:AttributeStatement>
            </saml:Assertion>

         </wst13:RequestedSecurityToken>
      </wst13:RequestSecurityTokenResponse>
   </soapenv:Body>
</soapenv:Envelope>

Actual response:

<soapenv:Envelope">
   <soapenv:Body>
      <wst13:SecResponse">
         <wst13:SecToken>

            <saml:Assertion ID="A-123"
                    xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion">
               <saml:AttributeStatement>
                  <saml:Attribute Name="ClientID">
                     <saml:AttributeValue
                             xsi:type="xsd:string"
                             xmlns:xsd="http://www.w3.org/2001/XMLSchema"
                             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">hello</saml:AttributeValue>
                  </saml:Attribute>
               </saml:AttributeStatement>
            </saml:Assertion>

         </wst13:RequestedSecurityToken>
      </wst13:RequestSecurityTokenResponse>
   </soapenv:Body>
</soapenv:Envelope>

You can see the difference in saml:Assertion element (see at namespaces defined in this element), and saml:AttributeValue element (also see at namespaces defined in this element).

So the question is how can I move the xsi and xsd namecpaces definition from saml:AttributeValue to saml:Assertion element?

What I already tried:

• I created my own namespace mapper (extends NamespacePrefixMapper) to be able to overwrite generated namespace prefixes. Also in this class I was able to move my xmlns:xsi to the root element but I don't want to move it to the root element, but to saml:Assertion element...
• I tried also add marshaller listener, but it looks that it works like above method or I don't know how I can use this listener in a proper way.