Set line number of XmlError?

After schema validating an XML instance loaded from disk I would like
to perform some extra programmatic validations not covered by the XML
schema. For the extra validation I hope to re-use xmlbeans XmlError
and XmlException. However if I create an XmlError using:

XmlError.forObject(message,XmlObject);

..then when I print the error the message contains no line number. I
tried experimenting with XmlValidationError instead passing a
XmlCursor to the factory method but that didn't help either. How do I
set the line number of the error when all I have is the XmlObject or
parent XmlObject?