Many of us find it bit diffficult what went wrong during EV OWA configuration and we have to google around. Here Symantec listt out all the relevant articles required for this procedure for all version of Exchange starting 2003 till 2010 (includes mixed mode)
Take a look on step by step procedure explained in details.
There are question based on your scenarios, pre-requisite readiness etc.
http://www.symantec.com/business/support/index?page=landing&key=50996
