In order to configure the custom port, you will need to configure the client port and the default SQL port.
In the SQL Server Configuration Manager (Start -> Microsoft SQL Server 2008 -> Configuration Tools -> SQL Server Configuration Manager) : Expand the SQL Native Client and double click on Client Protocols
Right Click on TCP/IP and change the default port to the one that you would like to work with, then OK
Then expand the SQL Server Network Configuration and highlight the Protocols for MSSQLSERVER (or the instance name)
From the righthand side right click on TCP/IP -> Properties.
Change the TCP Port in the correct places (in the IP addresses that you would it to be changed for example IP1, IP2 ) make sure that you scroll down and change the IPAll as well to the custom port. The TCP Dynamic port should be blank under all the IPs, if you see 0, please be sure to delete it.
Now restart the SQL server services and go to the Notification Server.
Go to -> Settings Notification Server -> Database Settings
In the SQL Server name, type the ip address comma custom port number for example 192.168.1.1,4433
After you have changed the server name, make sure that the option Use existing database is checked and the correct database is selected.
Click Save Changes it should restart the altiris service and now the custom port should be working, you would have to repeat the same steps for all of your Notification Servers.
Symantec Management Platform 7.5
SQL Server 2008 R2