Do you need something right away? Can you wait for and upgrade to 6.0? I assume the database adapters will be the first adapters moved to the new architecture (someone correct me if I’m wrong) and I believe that will give you what you’re after.
You could use the ES/IS package, which will transfer the notification from ES to IS in a pretty straightforward fashion.
If you want a direct connection to IS, you’ll need to craft your own solution, mimicking the functionality of the JDBC adapter. This is easier than it sounds. Basically you define a couple of tables and set up a scheduled service to poll the tables. There are a couple of techniques to follow to avoid duplicate notifications, in the event of failures at different times.