xsi:type attributes not being created in XML document instances when required

When an XSD element or its type is marked as abstract, the concrete elements used in the instance document to represent the abstract element must contain an xsi:type attribute with a concrete type as a value. It seems the best way to handle this in the future would be to add a new "type criteria" property and editor to transformations that would behave somewhat like the choice criteria editor. The editor would prompt the user specify one or more concrete types along with criteria used by the server to determine which type to use for a given set of data. This defect is a carryover from defect 20067 in Defect Tracker.