Can´t get IDispatch

Hello. I'm trying to dinamically create a COM object made with VB4.0 into a C++ 4.0 application. I can create the object with the IUnknown interface, but the call to QueryInterface for IDispatch fails.

I have tried with the same object compiled with VB5.0, and everything went OK. With OleView, I could see the coObject into the type library of the VB4.0 object doesn´t support IDispatch, but vb5.00 do.

Do you know why the vb4.0 doesn´t support IDispatch? How can I call an automation function without this interface?.

Thanks.