type information in return values?

[Paul Andrews]

When a return value is a complex bean (i.e. beans within beans), is it
possible to force the xsi:type of the elements to get set. I need this
because certain attributes are defined in terms of a common super-class,
but a return value would typically set that attribute to one of the
sub-classes. Unless the xsi:type can be set I have no way of knowing
what the sub-class actually was.