I've been setting up an SQL Server for a small business, and since our server company has blocked the default port, I have had to choose an alternative. After configuring the ports in various places - Windows Firewall, SQL Configuration Manager - I found that whatever I did would not work.
After a bit of searching, I found the answer.
When entering the server name into the field, instead of using the traditional 'host:port' scheme, Microsoft have decided to use a non-standard approach.
The correct naming scheme is: Host,Post\InstanceName (note the comma!)
Try it, worked for me. Leave a comment if you can't get it to work.