How to convert this Apache CXF endpoint definition to work in spring-ws - spring

Question

I have an old CXF application that I am trying to convert to spring-ws. Here's the endpoint:
<!-- The service endpoint-->
<jaxws:endpoint id="storeService"
implementor="#storeServiceImpl"
address="/store">
<!--interceptor for basic security. -->
<jaxws:inInterceptors>
<bean class="org.apache.cxf.ws.security.wss4j.WSS4JInInterceptor">
<constructor-arg>
<map>
<entry key="action"
value="UsernameToken"/>
<entry key="passwordType"
value="PasswordText"/>
<entry key="passwordCallbackRef"
value-ref="storeCallback"/>
</map>
</constructor-arg>
</bean>
</jaxws:inInterceptors>
<jaxws:properties>
<entry key="security.enable.nonce.cache" value="false" />
<entry key="security.enable.timestamp.cache" value="false" />
<entry key="security.timestamp.timeToLive" value="600000000" />
<entry key="ws-security.must-understand" value="false" />
</jaxws:properties>
</jaxws:endpoint>
I get how to setup spring-security so that I do not have to use the old security interceptor.
The issue I am running into is: How do I configure the end point in spring-ws to use properties that I define?
The mustUnderstand property in particular is crucial to using spring-ws. I am getting the so-called "famous" mustUnderstand error which is described in:
Spring-WS WSA header contains hardcoded mustUnderstand attribute
Any help will be appreciated!
PS Partial payload being sent to the service:
<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:ser="http://example.com/" xmlns:req="http://xmlns.example.com/salesforce/notifications/request">
<soap:Header />
<soap:Body>
<ser:setStore>
<PayloadRequest xmlns:ns2="http://xmlns.example.com/salesforce/notifications/request" xmlns:ns3="urn:sobject.enterprise.soap.sforce.com">
<req:metadata>
<ns2:Version_Number__c>1.0</ns2:Version_Number__c>
<ns2:Time_Stamp__c>2015-11-09T23:41:01.753Z</ns2:Time_Stamp__c>
</req:metadata>
<req:payload>
...
</req:payload>
</ser:setStore>
</soap:setStore>
</soap:Envelope>