Indeed an excellent helper class!
One thing to point out: I ran into a rights issue recently. It seems that the Security Equivalence of the 'Driver User' needs supervisor rights to the Driver object. I'm not sure why, because I would expect write rights to the attribute DirXML-AccessSubmitCommand should be sufficient (am I missing something?). Without these rights a Throwable is not handled by the code (bug):
com.novell.xml.xpath.XPathEvaluationException: function call to 'dxqueue:sendQueueEvent' resulted in an error: 'java.lang.NoSuchMethodError: com.novell.nds.dirxml.engine.NdsDtd.createStatusDocument(Ljava/lang/Throwable;Lcom/novell/nds/dirxml/engine/OperationData;)Lorg/w3c/dom/Document;