Connecting to an SQL server instance without using square brackets to avoid backslash
Create a Server Alias to point to your named instance.


  In SQL Server Configuration Manager, expand SQL Server Native Client
  Configuration, right-click Aliases, and then click New Alias.
  
  In the Alias Name box, type the name of the alias. Client applications
  use this name when they connect.
  
  In the Server box, type the name or IP address of a server. For a
  named instance append the instance name.
  
  In the Protocol box, select the protocol used for this alias.
  Selecting a protocol, changes the title of the optional properties box
  to Port No, Pipe Name, or Connection String.


If you're having trouble getting the client to connect via an alias, I'd suggest detailing the error message in a separate question.