restarting a seed after disconnection of external HD

hey all , just wondered if some one could help me , i use utorrent 1.8.4 and save my dl's to an external HD. My problem lies when i game ,i play World of warcraft and usually when doing just random stuff in game i will seed but 4 nights a week i do whats called raiding where myself and up to 24 other players will enter a dungeon creating alot of in game lag while seeding ,so i stop and disconnect external. Would like to reseed while computer is idle and ive checked with the utorrent site and it says to use the .torrent file to start reseeding but there are no .torrent files in the list.do i have to create a new torrent and if so what all is recomended to get it reseeding , thnx for the time

ahh, ok i usually dont save the meta but will from now on thnx