I created a simple Unit test in NHibernate.Tests
which helps me figured out that the way NHibernate config event is a tiny bit strange (only to me)....
It recognizes
<listener class='NHibernate.Test.Event.TestPostInsertEventListener,NHibernate.Test' type='post-insert' />
It also tries to recognize the Hibernate way
<event type="post-insert"/>
<listener class="NHibernate.Test.Event.TestPostInsertEventListener,NHibernate.Test" type="post-insert" />
</event>
However, as you might already noticed on the above code, NHibernate still requires the type attribute in the listener tag.
anyway, I don't think this is a big deal though. The attached is a patch with minor unit test about this configuration. I posted it here just in case anyone think it might be helpful.