Failure to deploy SOAPProxy action on SOA-P 5: org.jboss.soa.esb.ConfigurationException: 'url' property is not a valid URI.

Issue

We are trying to deploy an esb archive containing a SOAPProxy action, which fails due to an error while the wsdl file:

Caused by: org.jboss.soa.esb.ConfigurationException: Unexpected exception while instantiating action instance
    at org.jboss.soa.esb.listeners.message.ActionProcessorMethodInfo.getActionClassInstance(ActionProcessorMethodInfo.java:359)
    at org.jboss.soa.esb.listeners.message.ActionProcessorMethodInfo.getActionClassInstance(ActionProcessorMethodInfo.java:340)
    at org.jboss.soa.esb.listeners.message.ActionProcessingPipeline.<init>(ActionProcessingPipeline.java:275)
    at org.jboss.soa.esb.listeners.message.MessageAwareListener.doInitialise(MessageAwareListener.java:186)
    ... 82 more
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at org.jboss.soa.esb.listeners.message.ActionProcessorMethodInfo.getActionClassInstance(ActionProcessorMethodInfo.java:355)
    ... 85 more
Caused by: org.jboss.soa.esb.ConfigurationException: java.io.IOException: Failed to create RemoteWsdlLoader instance.
    at org.jboss.soa.esb.actions.soap.proxy.SOAPProxy.<init>(SOAPProxy.java:202)
    ... 90 more
Caused by: java.io.IOException: Failed to create RemoteWsdlLoader instance.
    at org.jboss.soa.esb.actions.soap.AbstractWsdlContractPublisher.getWsdl(AbstractWsdlContractPublisher.java:195)
    at org.jboss.soa.esb.actions.soap.proxy.SOAPProxyWsdlLoader$Puller.pull(SOAPProxyWsdlLoader.java:522)
    at org.jboss.soa.esb.actions.soap.proxy.SOAPProxyWsdlLoader.pullLocations(SOAPProxyWsdlLoader.java:227)
    at org.jboss.soa.esb.actions.soap.proxy.SOAPProxyWsdlLoader.pullLocations(SOAPProxyWsdlLoader.java:201)
    at org.jboss.soa.esb.actions.soap.proxy.SOAPProxyWsdlLoader.pullLocations(SOAPProxyWsdlLoader.java:229)
    at org.jboss.soa.esb.actions.soap.proxy.SOAPProxyWsdlLoader.pullLocations(SOAPProxyWsdlLoader.java:233)
    at org.jboss.soa.esb.actions.soap.proxy.SOAPProxyWsdlLoader.pullLocations(SOAPProxyWsdlLoader.java:233)
    at org.jboss.soa.esb.actions.soap.proxy.SOAPProxyWsdlLoader.pullLocations(SOAPProxyWsdlLoader.java:201)
    at org.jboss.soa.esb.actions.soap.proxy.SOAPProxyWsdlLoader.load(SOAPProxyWsdlLoader.java:161)
    at org.jboss.soa.esb.actions.soap.proxy.SOAPProxy.<init>(SOAPProxy.java:197)
    ... 90 more
Caused by: org.jboss.soa.esb.ConfigurationException: 'url' property is not a valid URI.
    at org.jboss.soa.esb.http.Configurator.getTargetURI(Configurator.java:64)
    at org.jboss.soa.esb.http.configurators.HttpProtocol.configure(HttpProtocol.java:77)
    at org.jboss.soa.esb.http.HttpClientFactory.createHttpClient(HttpClientFactory.java:84)
    at org.jboss.soa.esb.actions.soap.RemoteWsdlLoader.<init>(RemoteWsdlLoader.java:59)
    at org.jboss.soa.esb.actions.soap.AbstractWsdlContractPublisher.getWsdl(AbstractWsdlContractPublisher.java:193)