I noted that objects deleted from RM do not appear in the "Manage Deleted Items", only the objects deleted from DM do. Does anybody know if it is possible to transfer the deleted items from RM to the "Manage Deleted Items" so that if deletion is done by mistake it can be overturned?
I think the requirements for RM prohibit the "undelete". Deleted stuff stays deleted.
Whether content appears in the "manage deleted items" is controlled by the archive settings for the type and the store. You may be able to turn archiving on.