Enterprise Manager

If anyone could help with this I'd be very grateful;

I have created user defined metrics for alerting RMAN backup job success. When tested at the SQLPlus prompt, the SQL for the user defined metric always shows an output as desired. However, I now go to get OEM (in use with dbconsole, no grid control) to display the alert; the UDM works, giving a collection time as needed, but does not alert (as per alerts in last 24 hours), and no email comes through. All the emailing part is set up properly, and other alerts can come through.

My question is; is there an easier way of getting email alerts of RMAN backup completion/failure other than through user defined metrics?

Thanks, DW