Short answer: it is probably not worth the effort.
: CFD IDispatch, VBA. , VBA, , typelib "" CFD IUnknown. , Microsoft CFD typelib. typelib ( IDL SDK), typelib , (, , regsvr32 COM-). , , typelib VBA Vista . .NET, , System.Windows.Forms.FileDialog, VBA - , , ( ++/CLI DLL-), .NET.
, ...:) !