calling a soap client from a different package

Hi,
i have generated a proxy (cxf 2.7.8) for a soap service which i can call fine from the same package.
When I try to call the proxy from a different package, it fails to create the jaxb context and i get this error message:

can't parse argument number: ''{0}''
java.lang.IllegalArgumentException
at java.text.MessageFormat.makeFormat(MessageFormat.java:1420)
at java.text.MessageFormat.applyPattern(MessageFormat.java:479)
at java.text.MessageFormat.<init>(MessageFormat.java:363)
at java.text.MessageFormat.format(MessageFormat.java:835)
at com.sun.xml.bind.v2.model.impl.Messages.format(Messages.java:133)
at com.sun.xml.bind.v2.model.impl.ReferencePropertyInfoImpl.calcTypes(ReferencePropertyInfoImpl.java:185)
at com.sun.xml.bind.v2.model.impl.ReferencePropertyInfoImpl.link(ReferencePropertyInfoImpl.java:387)
at com.sun.xml.bind.v2.model.impl.ClassInfoImpl.link(ClassInfoImpl.java:1272)
at com.sun.xml.bind.v2.model.impl.RuntimeClassInfoImpl.link(RuntimeClassInfoImpl.java:197)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.link(ModelBuilder.java:454)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.link(RuntimeModelBuilder.java:138)
at com.sun.xml.bind.v2.runtime.JAXBContextImpl.getTypeInfoSet(JAXBContextImpl.java:469)
at com.sun.xml.bind.v2.runtime.JAXBContextImpl.<init>(JAXBContextImpl.java:303)
at com.sun.xml.bind.v2.runtime.JAXBContextImpl.<init>(JAXBContextImpl.java:142)
at com.sun.xml.bind.v2.runtime.JAXBContextImpl$JAXBContextBuilder.build(JAXBContextImpl.java:1174)
at com.sun.xml.bind.v2.ContextFactory.createContext(ContextFactory.java:162)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at javax.xml.bind.ContextFinder.newInstance(ContextFinder.java:248)
at javax.xml.bind.ContextFinder.newInstance(ContextFinder.java:235)
at javax.xml.bind.ContextFinder.find(ContextFinder.java:432)
at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:637)
at org.apache.cxf.common.jaxb.JAXBContextCache$2.run(JAXBContextCache.java:331)
at org.apache.cxf.common.jaxb.JAXBContextCache$2.run(JAXBContextCache.java:329)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.cxf.common.jaxb.JAXBContextCache.createContext(JAXBContextCache.java:329)
at org.apache.cxf.common.jaxb.JAXBContextCache.getCachedContextAndSchemas(JAXBContextCache.java:230)
at org.apache.cxf.jaxb.JAXBDataBinding.createJAXBContextAndSchemas(JAXBDataBinding.java:468)
at org.apache.cxf.jaxb.JAXBDataBinding.initialize(JAXBDataBinding.java:325)
at org.apache.cxf.service.factory.AbstractServiceFactoryBean.initializeDataBindings(AbstractServiceFactoryBean.java:86)
at org.apache.cxf.wsdl.service.factory.ReflectionServiceFactoryBean.buildServiceFromWSDL(ReflectionServiceFactoryBean.java:426)
at org.apache.cxf.wsdl.service.factory.ReflectionServiceFactoryBean.initializeServiceModel(ReflectionServiceFactoryBean.java:528)
at org.apache.cxf.wsdl.service.factory.ReflectionServiceFactoryBean.create(ReflectionServiceFactoryBean.java:264)
at org.apache.cxf.jaxws.support.JaxWsServiceFactoryBean.create(JaxWsServiceFactoryBean.java:215)
at org.apache.cxf.frontend.AbstractWSDLBasedEndpointFactory.createEndpoint(AbstractWSDLBasedEndpointFactory.java:102)
at org.apache.cxf.frontend.ClientFactoryBean.create(ClientFactoryBean.java:91)
at org.apache.cxf.frontend.ClientProxyFactoryBean.create(ClientProxyFactoryBean.java:157)
at org.apache.cxf.jaxws.JaxWsProxyFactoryBean.create(JaxWsProxyFactoryBean.java:142)
at org.apache.cxf.jaxws.ServiceImpl.createPort(ServiceImpl.java:493)
at org.apache.cxf.jaxws.ServiceImpl.getPort(ServiceImpl.java:359)
at org.apache.cxf.jaxws.ServiceImpl.getPort(ServiceImpl.java:350)
at javax.xml.ws.Service.getPort(Service.java:119)
...

What is the reason for this behavior and how I can I fix it?

Thanks,
Johannes