User activity Report Does not show name of sites in tmg2010

hi guys

i set up a tmg 2010 sp2 server in our network as an edge server.tmg hs joined to our domain. i want to log some users for which sites thery are going.report only show the ip address of sites that user gone.whats should i to show report by name of sites?

i can ping any sites by name .so there is no dns problem

thanks