Auditing 'EXSP' events

Informix 12.10 Solaris 10 I am attempting to use onaudit to monitor the execution of stored procedures. I have enabled auditing, with a default mask of 'EXSP'. I'm getting a lot of data, and seems to be mostly working. EXCEPT, that the ausit log does not show any record of a certain SPL that is executed periodically via the Scheduler. There is simply no entry in the audit log for it. Yet, if I examine the ph_run table, I observe that it is executing at the set times, its duration is what we expect, and the return code = 0. I wonder why it doesn't show up in the audit log file? Just for grins, I also added the 'SCSP' event to the _default mask (because the command in the Scheduler is "EXECUTE blah blah". Still doesn't appear. I think I am not understanding something about onaudit. Comments appreciated. DG