I followed a post on Lifehacker for installing iOS5 GM on my iPhone 4 the other day, part of the instructions were to install 10.5 beta as that version of iTunes was required. Now that iTune 10.5 is available for download, how can I replace 10.5 beta with 10.5 'normal'. I'm using OSX 10.7 Lion, if i try and do a update it says everything is up to date.