This works to a point, but I am embedding an XML fragment in the request with a property expansion, and turning on 'Entitize Properties' for the Request causes attribute value delimiters in the fragment to be entitized, eg.:
[tt:2cq14upm][/tt:2cq14upm]
becomes
[tt:2cq14upm][/tt:2cq14upm]
Similarly, double quotes around attribute values are changed to ".
[tt:2cq14upm][/tt:2cq14upm]
becomes
[tt:2cq14upm][/tt:2cq14upm]
Since the Entitize setting is for the whole request, there is no way to protect the XML fragment from what appears to be a simple search & replace.
Perhaps for a future release you might consider extending property expansions, so for example ${& } would entitize the referenced property and ${! } would protect the property from any global entity replacement. This would provide finer grained control while not breaking existing functionality.