[otrs] Is there a way to set a dynamic field to NULL via a Generic Agent job?

Hi all, The job config UI provides only a textbox which, if completed will lead to the DF being set to the completed value and if left empty will lead to the DF not being touched by the job. I'm hoping there's some magic value (i.e. __NULL__) which, if provided, will do what I need. Thanks, Bogdan