Shedule a job as system user

Hi,

I need to know how I could schedule a job (sm36/sm37) as a user of type System user. Obviously the straight forward approach of logging on with the user and then just defining and scheduling the job doesn't work since system users cannot log on via SAP GUI.

Is there some other way of switching user once logged on to a SAP system. Or how could this be solved otherwise?

Regards,

Christian