from what i can determine there is no alert catagory for 'Missed Jobs' the missed job shows up in job hostory but there is no alert generated for this event. this is the job history of a failed/missed job;
Job name : 216B User's (Full)
Job type : Backup
Job status : Missed
Job log :
Server name :
Selection list name : User's
Device name :
Target name :
Media set name :
Error category :
Error : e000e020 - The job was scheduled to run, but the availability window closed before the job could start. There may not have been any destination devices available during the window, or the job may have been submitted to run when the window was closed.