Correct the vendor who is receiving the document. Quotes and other special characters need to be escaped. That is proper handling of the xml and working by design within the xmlOutput Stage.
As a solution, though dangerous (what "other" escape possibilities is this application ignoring?) is to send the xmlOutput content to a single column (create a large column on your output link, like "myXMLcontent" with varchar and length of 99999 or similar) and put a single slash "/" in the Description. Send that into a Transformer and just use something like ereplace() to zap all of the items you don't want back into whatever you need...
Thanks. In some contexts, that could be considered a bug. Proper behavior is to perform the escape. I haven't checked in awhile....the hierarchical stage may only do it when validation on input is used.