The Job Manager will not register/list a job just because the jobfile has been 'saved as XML'. It will have to be scheduled (ie: registered with the Windows Scheduler) as Job manager reads its information from the Windows Scheduler (but filters it – very simply actually: it lists scheduled jobs with 'sja' executable).
You may schedule a job without actually setting a time or interval for its execution. If you do this Job Manger will list the job.
You are not the first user getting confused about this .. and I think we should soon look into an updated implementation.