I've been digging around and found the publishing point sub-event
WMS_EVENT_PUBLISHING_POINT_STREAM_END, which is (*I think*) exactly
what I need.  Problem is I can't figure out when the thing fires.
I've written an event notification plugin that watches for this event
as well as gone the VBScript/WMS Active Script Event Handler route
with no luck.  The docs say:

'The publishing point has stopped sending a stream. Because a
publishing point does not automatically stop when an encoder, for
example, sends an end-of-stream notification, this event can be used
to determine when the stop method should be called to disconnect all
clients.'

The way I read that, once I stop an encoder stream the publishing
point will continue to stream (I would guess briefly) until it's
buffer/whatever runs out.  Once that happens I would expect
WMS_EVENT_PUBLISHING_POINT_STREAM_END to fire.  I'm I interpreting
this wrong?  Can anyone point me in the right direction?

Thanks