Line 217 in org.codehaus.xfire.aegisAegisBindingprovider.java seems quirky to me, it causes an Exception with null value complex type parameters. Caused by: javax.xml.stream.XMLStreamException: Attribute not associated with any element at com.sun.xml.internal.stream.writers.XMLStreamWriterImpl.writeAttribute(XMLStreamWriterImpl.java:600) at org.codehaus.xfire.aegis.stax.AttributeWriter.writeValue(AttributeWriter.java:45) ... 36 more The exeption is right, there is no open tag at this context. A possible fix could be 213 MessageWriter mw = new ElementWriter(writer); 214 215 /* if (type.isNillable() && value == null) 216 { 217 mw.writeXsiNil(); 218 return; 219 } */ 220 221 context.setProperty(CURRENT_MESSAGE_PART, p); commented block should be removed. Null value parameters are working after that patch. Fixed request parameter output as sample: <ns5:ArrayOfSortOption_3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns5="http://types.xlocate.xserver.ptvag.com" xmlns:ns4="http://wrappertypes.service.jabba.ptvag.com" xmlns:ns3="http://exception.core.jabba.ptvag.com" xmlns:ns2="http://common.xserver.ptvag.com" xmlns="http://xlocate.xserver.ptvag.com" xsi:nil="true"></ns5:ArrayOfSortOption_3>