cannot access flash from rjs helper

all is in the title :). I've got an rjs file calling "page.ajax_flash_alert". This method is defined in Application helper in which i do this : if flash.size > 0   flash.each do |key, msg|     page.insert_html(:bottom, :alert, content_tag(:div, msg, :class => key))   end end

But the flash content is lost. When i put the code directly in the rjs file it works.

Someone can help?

regards