Object of the present invention is to provide a method or a system by which an operator without skills in bending operation can easily and quickly perform precise bending operations on a sheet workpiece by following skilled operator’s experience, hints or data. The key assembly is rigidly fixed to the framework, and is covered, towards the outer side of the door, by the means for supporting the rear-view mirror and is accessible from the outside through a seat made in the supporting means themselves. All calls are connected on regular channels until the regular channels are all full. Changes from sites not in the persistent membership are discarded. Hereby, one or more implant devices can be implanted in the vessels and can subsequently be heated by external energy-providing means.