Ok, I'm trying to do this but I'm obviously missing something.
I put this in bulk-mail/tcl/apm-callback-procs.tcl:
ad_library {
    APM callback procedures in the bulk-mail::apm namespace.
    @creation-date October 31 2003
    @author Janine Sisk
    @cvs-id $Id$
}
namespace eval bulk-mail::apm {}
ad_proc -public bulk-mail::apm::after_mount {
  {-package_id:required}
  {-node_id:required}
} {
  This is a comment about what this proc does
} {
  ns_log Notice "J9: in bulk_mail::apm::after_mount"
}
Then I created an after_mount callback for bulk-mail in the APM, using bulk-mail::apm::after_mount as the proc name, and restarted the site.  There are no errors in the error log, but my ns_log is not being executed.
What else do I need to do?