Changing the Login / Authentication Mode programmtically via SMO
Here are some instructions how to change the Login / authentication mode via Code. It just uses plain SMO capabilites:
After this you will have to make sure that the Service is restarted, if you want this to do via SMO look at the following sample. You need to know the ServiceName your Service instance you want to restart is running:
-Jens
The other options are mentioned here: https://www.sqlserver2005.de/Screencast/Screencast.aspx?ScreencastId=5