Form empty non-string mandatory elements create invalid xml

If the wsdl allows a non-string mandatory element to be 'nillable', then when the value on the Form is left blank SoapUI should generate the xml element as not only empty, but also with the attribute
xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
As the empty element currently created in these circumstances by SoapUI without this is invalid XML.