从VBA (Excel)访问VSTO应用程序插件类型

We have a VSTO application-addin (not a document-addin) for Excel, and we want to expose an event to VBA code so that the VBA macro can do some action when this event fires in the addin. How can I get the VBA code to be able to subscribe to an event defined in the VSTO application-addin?We have a VSTO application-addin (not a documen