that isn't true, when i've ran liveinfo in the past it detected all my drives straight away, so both my pc drive and a not yet formatted xbox drive was detected. so it might have something to do with making sure that one drive is set to master and the other secondary. if not then don't use liveinfo, in my experience liveinfo along with dos unlocking tools like unlockx is rubbish, don't use that tutorial, use this one instead
http://forums.xbox-scene.com/index.php?showtopic=244043it uses a program called xboxhdm (yes its linux based, but don't be scared, i can't use linux!)
i found unlockx and similar programs to be rubbish, they didn't lock my drives properly so i kept getting error 6's. and don't use windows based fatx tools (i.e. hdd driver), they are also rubbish, they don't always copy drive contents identically.
if you need any help using xboxhdm (if you decide to use it) then PM me and i'll give you all the help you need.