I've noticed that if I go to the newsletters module, I can subscribe users to newsletters.

If I delete a user, his or her subscriptions are removed.

However, the only API sample I have found (http://devnet.kentico.com/Knowledge-Base/E-mail-Engine/How-to-subscribe-user-to-newsletter-using-API.aspx) adds subscribers as new subscribers (not as existing users).

Then if I delete the user, the subscriber is not tied to the user, and the subscription remains active.

How can I use the API to subscribe a user to a newsletter as a 'user'?

Second, does the OnBeforeDelete event in the CustomDataHandler fire when a user is deleted? If so, I can use that to clean up some of my existing subscriptions.

Thanks,
Joe Hoppe