virtual destructors - doesn't seem to work

["kat-Zygfryd" <6667@wp.pl>]

It doesn't seem to work :(
Look:

-- errata to previous code
type CBase is access all Base'Class;
type CDerived is access all Derived'Class;
-- /errata

procedure Dispose(self: in out CBase) is
begin
    Put_Line("CBase.Dispose");
end Dispose;

procedure Dispose(self: in out CDerived) is
begin
    Put_Line("CDerived.Dispose");
end Dispose;

function create_derived return CDerived is
begin
    return new Derived;
end create_derived;

declare
    B: CBase := CBase(create_derived);
begin
    Dispose(B); -- outputs "CBase.Dispose"
end;

what am I doing wrong?

Zygfryd