Good Day

I have a project which was in .NET 4 , i used VS2010 on it. I later opened the Project in VS2012 and Build everything that build well in VS2010 , but it gives me some error relating to accessing the WCF functions. now in .NET 4 , we can create our service and reference it on the SIlverlight project like this

Code:
 AuditSystem.DataLayer.DataAccessLayerClient business = new AuditSystem.DataLayer.DataAccessLayerClient();
            business.GetAllUsersAsync();
            business.GetAllUsersCompleted += new EventHandler<AuditSystem.DataLayer.GetAllUsersCompletedEventArgs>(business_GetAllUsersCompleted);
but now in VS2012 this does not look like its possible. After my upgrade to VS2012(4.5) my project does not build

Can one explain why ?