Just define the bean as follows:
<jaxws:client id="soapClient"
serviceClass="${serviceClass}"
address="${serviceUrl}">
<jaxws:outInterceptors>
<ref bean="loggingOutInterceptor"/>
</jaxws:outInterceptors>
</jaxws:client>
<bean id="loggingOutInterceptor" class="org.apache.cxf.interceptor.LoggingOutInterceptor" />