A federal appeals court found that an insurance company does not owe a duty to defend on an auto policy, while another insurance company must do so on general liability, in a case where two workers were injured on a construction site.Southern Truss, Inc., a wood roof and floor truss maker, is being sued by two men who were injured by a power crane that was permanently attached to a truck it owns.Southern Truss has a commercial auto policy issued by Artisan and Truckers Casualty Co. and a commercial general liability …