i wrote override to_xml model method , right im trying hash attribute transformed set if symbol => values pair had no success. the result of intersected_categories method hash like: {:"1"=>["broken board", false], :"2"=>["sticking", false], :"3"=>["bottom tier missing", false], :"4"=>["bad i/l", false], :"5"=>["delamination", false], :"7"=>["sheet level - smile", false], :"8"=>["sheet level - frown", false], :"9"=>["missing ss", false]} the to_xml method def to_xml (options={}) xml = options[:builder] ||= builder::xmlmarkup.new(:indent => options[:indent]) xml.instruct! unless options[:skip_instruct] xml.wip @wip, :number => self.number, :start_time => self.wip_start_time, :end_time => self.wip_end_time, :line => self.system.name, :shift => self.shift, :...