Why do I have NullPointerException exception error when deploying a WEB Service that uses wsdllocation in JBoss EAP 6.1?

Issue

When deploying an application that contains a WEB Service that uses a custom WSDL (not generated by JBossWS) we have the following error:

ERROR [org.jboss.msc.service.fail] (MSC service thread 1-1) MSC000001: Failed to start service jboss.deployment.unit."mywebservices.jar".INSTALL: org.jboss.msc.service.StartException in service jboss.deployment.unit."mywebservices.jar".INSTALL: JBAS018733: Falha ao proceder com a fase INSTALL do deployment "mywebservices.jar"
    at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:127) [jboss-as-server-7.2.0.Final-redhat-8.jar:7.2.0.Final-redhat-8]
    at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1811) [jboss-msc-1.0.4.GA-redhat-1.jar:1.0.4.GA-redhat-1]
    at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1746) [jboss-msc-1.0.4.GA-redhat-1.jar:1.0.4.GA-redhat-1]
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) [rt.jar:1.6.0_26]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) [rt.jar:1.6.0_26]
    at java.lang.Thread.run(Thread.java:662) [rt.jar:1.6.0_26]
Caused by: javax.xml.ws.WebServiceException: java.lang.NullPointerException
    at org.apache.cxf.jaxws.EndpointImpl.doPublish(EndpointImpl.java:368)
    at org.jboss.wsf.stack.cxf.deployment.EndpointImpl.doPublish(EndpointImpl.java:67)
    at org.apache.cxf.jaxws.EndpointImpl.publish(EndpointImpl.java:250)
    at org.apache.cxf.jaxws.EndpointImpl.publish(EndpointImpl.java:536)
    at org.jboss.wsf.stack.cxf.configuration.NonSpringBusHolder.configure(NonSpringBusHolder.java:116)
    at org.jboss.wsf.stack.cxf.deployment.aspect.BusDeploymentAspect.startDeploymentBus(BusDeploymentAspect.java:128)
    at org.jboss.wsf.stack.cxf.deployment.aspect.BusDeploymentAspect.start(BusDeploymentAspect.java:67)
    at org.jboss.as.webservices.deployers.AspectDeploymentProcessor.deploy(AspectDeploymentProcessor.java:74)
    at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:120) [jboss-as-server-7.2.0.Final-redhat-8.jar:7.2.0.Final-redhat-8]
    ... 5 more
Caused by: java.lang.NullPointerException
    at org.apache.cxf.common.util.ASMHelper.getClassCode(ASMHelper.java:170)
    at org.apache.cxf.jaxws.WrapperClassGenerator.generateMessagePart(WrapperClassGenerator.java:320)
    at org.apache.cxf.jaxws.WrapperClassGenerator.createWrapperClass(WrapperClassGenerator.java:234)
    at org.apache.cxf.jaxws.WrapperClassGenerator.generate(WrapperClassGenerator.java:137)
    at org.apache.cxf.jaxws.support.JaxWsServiceFactoryBean.generatedWrapperBeanClass(JaxWsServiceFactoryBean.java:669)
    at org.apache.cxf.jaxws.support.JaxWsServiceFactoryBean.getExtraClass(JaxWsServiceFactoryBean.java:638)
    at org.apache.cxf.service.factory.ReflectionServiceFactoryBean.buildServiceFromWSDL(ReflectionServiceFactoryBean.java:428)
    at org.apache.cxf.service.factory.ReflectionServiceFactoryBean.initializeServiceModel(ReflectionServiceFactoryBean.java:538)
    at org.apache.cxf.service.factory.ReflectionServiceFactoryBean.create(ReflectionServiceFactoryBean.java:252)
    at org.apache.cxf.jaxws.support.JaxWsServiceFactoryBean.create(JaxWsServiceFactoryBean.java:205)
    at org.apache.cxf.frontend.AbstractWSDLBasedEndpointFactory.createEndpoint(AbstractWSDLBasedEndpointFactory.java:101)
    at org.apache.cxf.frontend.ServerFactoryBean.create(ServerFactoryBean.java:159)
    at org.apache.cxf.jaxws.JaxWsServerFactoryBean.create(JaxWsServerFactoryBean.java:211)
    at org.apache.cxf.jaxws.EndpointImpl.getServer(EndpointImpl.java:453)
    at org.apache.cxf.jaxws.EndpointImpl.doPublish(EndpointImpl.java:333)
    ... 13 more