When installing Configmgr 2012 to a dedicated SQL server with several Instances this is how..
U will need a dedicated SQL server or Instance for each site with Configmgr 2012.
Because of Collation settings and SQL replication.
Install a new SQL 2008 R2 Instance to the SQL Server.
The instance of SQL Server in use at each site must use the following collation: SQL_Latin1_General_CP1_CI_AS.
Name the Instance something meaningfull like SCCM... (this is only to be uses for SCCM)
Remember to run Service Packs and CUpdates only for that Instance.
Now, SQL will only set and use the port TCP 1433 to the first Default Instance. The Instances installed afterwards get a dynamic choosen port set. Configmgr 2012 does not support dynamic port for SQL.
So this can be set in the SQL Server Configuration Manager.
Select the name you choose to call the Instance. Then TCP/IP.
And for All the IP1, IP2, … delete the TCP Dynamic Ports (remove 0) and set the port nr you find available in the TCP Port. I've choosen 5033.
The SSB Port is also something to think of, depending on Your configuration.
Based on the name of the Instance, Configmgr will detect the port configured automatically. :-)