Xml for post data was invalid, Reference to undeclared entity 'Atilde'

[bumperbox]

When sending international characters this messages pops up "Xml for post data was invalid, Reference to undeclared entity 'Atilde'"

According to this Stackoverflow http://stackoverflow.com/questions/552957/, addChild() does not escape xml entities, whereas setting directly via $xml->$key does escape entities, removes the need to try and escape them ourselves first, as the current htmlentities() call doesn't do a good job of all xml entities

Also see this discussion https://community.xero.com/developer/discussion/32311/