Deserializes the DOM Element into a POJO whose type this Serializer is responsible for.
@param xml The XML representation of a Java object. If the type is primitive or simple (not a primitive, but serialized to a string), the value should be a DOM Text node inside the given Element.
@return A POJO constructed from the given XML. If the Element is empty
and the Serializer's type is a non-primitive, the method will return null.
@throws SoapFault
- If the XML is not a valid representation of the Serializer's type.