I dont want a work item in my inbox for a background activity

Hi guys

i have created a custom business object and created a new method in the custom business object to fetch data from SAP and send an email.

I then created a workflow with a single activity step and in the activity step i had given the method created.

when a PO is created this workflow will be triggered and the workflow should send an email to the external email id which is picked up from a custom table. So i am not expecting a work item in my sap inbox. But when i execute this workflow it is creating a work item. HOW DO I AVOID creating a work item in my workflow?

the method is with NO DIALOG and no mndatory parameter. any idea how to do this?