Hi:
Look on page 12 of the paper. The author says he is willing to share the Data step code. Since his method essentially bypasses both XMLMapper and PROC TEMPLATE, you would either need to write your own DATA step code or get the code from this paper author.
Also, note that on page 11 of his paper, he says that:
"An alternative to the LIBNAME XML engine for XML import and PROC TEMPLATE for export is to flatten the hierarchical XML into a numerically indexed representation that presents nothing new to the SAS programmer, unlike native XML. This method is the basis for the import and export of XML that takes place 100% in the familiar DATA step."
This flattening of the hierarchy would -still- mean that SAS is NOT checking the XML file for whether it is valid, well-formed or conforming to the schema or DTD. So it would be possible in this method for you to work with a badly formed, and/or invalid XML file.
cynthia