SQL Server Browser仅显示主机名，而不显示实例名称

I just setup a new Windows Server 2008 machine with an instance of SQL Server 2008 Express. The SQL Browser service does not appear to be working correctly. In Management Studio, browsing for servers shows the hostname of the new server, but not the instance name. When you choose the hostname form the list it doesn't connect. But I can connect manually by typing the hostname\instancename combination.I just setup a new Windows Server 2008 machine