Currently, only parameters that match fields configured in the routingConfig are honored (the others are ignored)
(NOTE: to make this even more reusable we might want to consider generating content for all parameters, even those that
do not have corresponding fields)
The routingConfig element defines a set of fieldDefs, each of which may have an xpathexpression for field evaluation.
This xpathexpression is used to determine whether the attribute's
StandardGenericXMLRuleAttribute.isMatch(DocumentContent,List) will
succeed. Each fieldDef may also have a validation element which supplies a regular expression against which
to validate the field value (given by the param map)