For information on converting to InterSystems IRIS, see the
InterSystems IRIS Adoption Guide
and the InterSystems IRIS In-Place Conversion Guide,
both available on the WRC Distributions page (login required).
Override XMLNew to allow for deserializing arrays of SOAP headers. This is to overcome problems with the XML Import of
array properties that contain polymorphic objects (i.e. any non-homogenous array).