Callback from Com Dll

[Nanni]

Hi to all

I am attempting, for the first time, to use a callback function from VB6 and
I need help with.

I have this Idl definition:

[
    object,
    uuid(1E8701D0-258F-43ED-9EDC-434FD16E922D),
    helpstring("Switcher Object")
] interface IBMDSwitcher : IUnknown
{
    HRESULT AddCallback([in] IBMDSwitcherCallback* callback);
    HRESULT RemoveCallback([in] IBMDSwitcherCallback* callback);
    ..others properties
    };

[
    object,
    uuid(6C6E4441-9421-4729-9951-988659E3A44A),
    helpstring("Switcher Callback Delegate")
] interface IBMDSwitcherCallback : IUnknown
{
    HRESULT PropertyChanged([in] BMDSwitcherPropertyId propertyId);
    HRESULT Disconnected(void);
};

I need to get the Disconnected Event.
AddCallback requires a pointer to IBMDSwitcherCallback

How can Assign Callback using AddressOf ?

Thanks for Help or Idea