I never used SQLExec from CMD window.
But after having installed SqlLocalDB.MSI (the inst file from MS for LocalDB based on SQL Server 2012 Express) I can connect to LocalDB using instance name "(localdb)\v11.0" from SQL Server 2012 Management Studio as well as from my application like to every other "normal" SQL Server 2012 database.
My app uses
SQLRETURN SQL_API SQLExecDirect
__in_ecount_opt(TextLength) SQLCHAR* StatementText,
from SQL.h (from MS) for SQL commands.
But from InstallAware the command "Detect MS SQL instances" does not detect LocalDB instances
and "Microsoft SQL Server Script" returns errors if called with instance name "(localdb)\v11.0".
For info about LocalDB see http://msdn.microsoft.com/en-us/library/hh510202.aspx