NAMESPACE_ERROR when attempting to add xmlns:foo="bar" attribute in Java SOAP message

Issue

When migrating from JBoss EAP 4 to EAP 5, the following code no longer works, throwing an exception with NAMESPACE_ERROR.

MessageFactory mf = MessageFactory.newInstance();
SOAPMessage message = mf.createMessage();
SOAPPart soapPart = message.getSOAPPart();
SOAPEnvelope envelope = soapPart.getEnvelope();
Name envelopeAttrib = sf.createName("xmlns:proc");
envelope.addAttribute(envelopeAttrib, "http://example.com/proc");