How to have event sub called from non-child process

I have an app that needs to be notified when another app triggers an event in its COM. I've registered it and I can see the event, but when I attempt to use the event, my event sub is not triggered.

How can I acces the running process' COM event in my app? The running app is not a child of mine, and I don't have access to the source of it. Do I need a Callback in the running app?

Thanks.

The simplest way would be to declare somthing as app1's com event, then your app's event will get triggered at the same time.