Change Log for PO attachments.

Hi Gurus,

Is it possible to change the object attachments within POs and activate Change history – User wants to see when someone ADDS or DELETES an attachment for audit purposes.

I know that an attchment can be created through services for object. But need to know with steps as to how i can record the change logs, if changes made to the attachment or deleted.

Regards

Pradeep.