Enterprise Manager

Hi there, can anyone help with the following:

I would like to display an alert on the OEM home page if a scheduled PL/SQL job fails, i.e. the underlying code generates an error. I have thought of tyring the following:

I can handle the failure as an exeception in the PL/SQL block and can then write an error record into an error table, I could then create a user defineable metric to check the number of rows in this table. The threshold of the metric would check if number of rows is > than zero thus raising an ALERT meeage in OEM.

I can't get the above solution to work, has anyone else tried to user the ALERT section of OEM in a similar way?

Many thanks for any guidance,
Richard