[configuration] Enable tcp\ip remote connections to sql server express already installed database with code or script(query)

I am deploying sql express with my application. I will like that database engine to accept remote connections. I know how to configure that manual by launching the sql server configuration manager, enabling tcp/ip connections, specifying the ports etc.. I am wondering if it will be possible to do the same thing from the command line.

Or maybe I will have to create a "SQL Server 2008 Server Project" in visual studio.

EDIT 1

I posted the same question in here but I will like to do the same thing on a instance of sql express that is already installed. Take a look at the question in here

EDIT 2

I found these links that claim on doing something similar and I still cannot make it work.

1) http://support.microsoft.com/kb/839980

2) http://social.msdn.microsoft.com/Forums/en-US/sqlexpress/thread/c7d3c3af-2b1e-4273-afe9-0669dcb7bd02/

3) http://www.sql-questions.com/microsoft/SQL-Server/34211977/can-not-connect-to-sql-2008-express-on-same-lan.aspx

4) http://datazulu.com/blog/post/Enable_sql_server_tcp_via_script.aspx

EDIT 3

As Krzysztof stated in his response I need (plus other things that I know that are required)

1 - enable TCP/IP

I have managed to do this when installing a new instance of SQLExpress passing the parameter /TCPENABLED=1. When I install sql express like in this example. that instance of sql express will have TCP/IP enabled

2 - Open the right ports in the firewall

(I have done this manualy but I belive I will be able to figure it out how to do it with c#) So far I have to play aroud with this console command:

netsh firewall set portopening protocol = TCP port = 1433 name = SQLPort mode = ENABLE scope = SUBNET profile = CURRENT

3 - Modify TCP/IP properties enable a IP address

I have not been able to figure out how to enable a IP, change a port etc.. I think this will be the step more complicated to solve

4 - Enable mixed mode authentication in sql server

I have managed to do this when installing SQL Express passing the parameter /SECURITYMODE=SQL refer to step 1's link.

SQL Server express requires this authentication type to accept remote connections.

5 - Change user (sa) default passowrd

By default the sa account has a NULL passowrd. In order to accept connections this user must have a password. I changed the default passowrd of the sa with the script:

ALTER LOGIN [sa] WITH PASSWORD='*****newPassword****' 

6 - finally

will be able to connecto if all the last steps are satisied as:

SQLCMD -U sa -P newPassword -S 192.168.0.120\SQLEXPRESS,1433

by typing that in the command line: the connection string in C# will be very similar. I will have to replace -U for user , -P for password and -S for data source. I dont recall the exact names.

I recommend to use SMO (Enable TCP/IP Network Protocol for SQL Server). However, it was not available in my case.

I rewrote the WMI commands from Krzysztof Kozielczyk to PowerShell.

# Enable TCP/IP

Get-CimInstance -Namespace root/Microsoft/SqlServer/ComputerManagement10 -ClassName ServerNetworkProtocol -Filter "InstanceName = 'SQLEXPRESS' and ProtocolName = 'Tcp'" |
Invoke-CimMethod -Name SetEnable

# Open the right ports in the firewall
New-NetFirewallRule -DisplayName 'MSSQL$SQLEXPRESS' -Direction Inbound -Action Allow -Protocol TCP -LocalPort 1433

# Modify TCP/IP properties to enable an IP address

$properties = Get-CimInstance -Namespace root/Microsoft/SqlServer/ComputerManagement10 -ClassName ServerNetworkProtocolProperty -Filter "InstanceName='SQLEXPRESS' and ProtocolName = 'Tcp' and IPAddressName='IPAll'"
$properties | ? { $_.PropertyName -eq 'TcpPort' } | Invoke-CimMethod -Name SetStringValue -Arguments @{ StrValue = '1433' }
$properties | ? { $_.PropertyName -eq 'TcpPortDynamic' } | Invoke-CimMethod -Name SetStringValue -Arguments @{ StrValue = '' }

# Restart SQL Server

Restart-Service 'MSSQL$SQLEXPRESS'