Hi ISK,
Although weighing the anchor is done automatically in that mission, it would not be the first action to be broken in an update. Unfortunately, that mission is now locked and cannot be examined.
Towing presents a rather difficult problem in the ship dynamics—though not as complex as it can be in Trainz with a 90-car drag over a rollercoaster like Marias Pass—that has not been solved in a completely satisfactory way.
I had no trouble towing AS with Sherpa, but that could depend upon where AS ends up when you drop the hook.
Regards,
Marty