To add 'incident' as an issue type so that staff can log new incidents directly from the Helpdesk you must be logged in as the primary manager or Helpdesk manager.
In order to auto-set the worktype also when a new issue is logged (this is required) now click the change settings button on the 'incident' row in the left hand pane.
Set the worktype options as above and click Confirm to close and save your settings. This ensures that Helpdesk issues with an issue type of 'incident' will automatically be assigned the appropriate worktype at the same time.