How to execute UNDO in an action?

Hi All,

I have created an action that applies different transformations to an image and saves the different transformed images. In the action, after saving each transformed image I have inserted UNDO using "Insert Menu Item...". Unfortunately, when I execute the action I get the error message "The command Undo is not currently available". How can I execute UNDO in an action? 

Regards,

Simone